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Chapter 6

Installing and Maintaining Landscape Plants

Michael DanaDepartment of Horticulture and Landscape Architecture

Learning Objectives

From reading and studying this chapter, you should be able to:

• Define the types of nursery stock commonly found in the landscape industry• Understand proper timing for planting• Describe general and specific planting techniques to maximize plant establishment success• Understand the reasons for and techniques of certain post-planting operations• Understand proper timing of fertilizer application for landscape plants• Describe fertilizer application techniques for routine and specialized situations• Understand the reasons for pruning• Dispel common myths about pruning• Understand proper timing for pruning and describe appropriate tools• Define basic and specific techniques for pruning a variety of woody landscape plants

Introductory Comments

This chapter presents the concepts and tech-niques involved in the establishment and man-agement of woody landscape plants. It coversplanting, fertilizing and pruning. Other aspectsof management, such as disease control, are dis-cussed in later chapters. The methods presentedhere (especially those for plant installation) arewhat might be called “best management prac-tices.” They are based on knowledge of plantphysiology and on observation and will usuallymaximize success in transplantation. However,they are not the only methods which can result insuccess. Differences in soil conditions, in degreeof care in plant handling, and follow-up manage-ment means many variations on these techniquesmay succeed. Experienced landscape horticul-turists often develop methods specific to their ar-eas which work for them and their customers.

Installing Landscape Plants

Types of Nursery Stock

Once you know what kind of plant you willinstall, you must decide if you intend to plant abare root, machine-balled, balled and burlappedor containerized plant. How you treat the tree orshrub at planting time will partially depend uponhow the roots were prepared for planting.

• Bare root — These are usually the least ex-pensive nursery plants and are generally lim-ited to deciduous plants only. They are dugwhen they’re dormant. You must protect theroots from drying out and from mechanicaldamage. You should plant them only whilethey are dormant (Figure 1).

Figure sketches by Kevin Allen.

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Figure 1. Bare root.

•� Machine balled — These plants are dug bare-root, then the roots are packed in sphagnummoss peat or wood shavings and wrapped inplastic. Handle them carefully to avoid break-ing roots. These too should be planted whilethey’re still dormant (Figure 2).

Figure 2. Machine balled.

•� Balled and burlapped (B&B) — Theseplants are dug from a production field with anundisturbed ball of soil around the roots. Dig-ging is done while plants are dormant or justbeginning to come out of dormancy in thespring, or just as they go into dormancy (or

later) in the fall. Digging of larger stock isusually done by machine. On smaller mate-rial, workers wrap the soil in burlap, bind itwith twine or wire and pin it together withnails (Figure 3). Machine-dug plants areplaced into a burlap-lined wire basket. Oncetied with twine, the wire basket is crimpedfor tightness

Figure 3. Balled and burlapped.

•� Containerized plants — Plants in pots maycome from several different production back-grounds. They may have grown in the con-tainer for a growing season or more (Con-tainer Grown or CG) (Figure 4); they mayhave been dug bare-root and planted in thepot earlier that same year (Potted); or theymay have been field-grown, dug with a soilball, and placed into the container (Field Pot-ted or FP).

Figure 4. Container grown.

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Both balled & burlapped and containerizedplants usually cost more than bare root plants.However, since you move soil with the roots,such plants are more likely to survive. Contain-erized plants that have grown in the container forat least one full growing season (CG) have theadded advantage of fully intact root systems atplanting. A portion of the root system is cut offB&B stock and some containerized plants (FP)at the time of digging.

Handle balled and burlapped and container-ized plants only by the soil ball or pot. Never liftthem by the trunk or crown. If you don’t plantthem immediately, put them in a cool, shelteredarea. Water them to keep the ball or containersoil moist (usually once a day), but don’t standthe root ball or the container in water.

Try to acquire nursery stock just before youintend to put it in the ground. You can hold bare-root plants for several days in a cool, shelteredlocation by covering the roots with a mulch suchas sawdust, wood chips, or shredded bark. Waterthem daily, but don’t let roots stand in water.

If you plan to hold bare-root or B&B stockwithout planting for more than a week, “heel in”or temporarily plant it in a sheltered spot. To heelin bare-root stock, dig a trench with one slopingside deep enough to accommodate roots (Figure5). Spread the roots in the trench; rest the trunk

against the sloping side. Mulch the roots and thelower stem with soil, sand, sawdust, or sphag-num moss. Keep the mulch moist until you movethe plants to a permanent location. To heel inB&B stock, simply mound mulch over the soilballs creating a temporary, mini-planting berm.

For containerized nursery stock, until it isplanted, you’ll need to keep the containers wa-tered and protected from physical damage, desic-cation and overheating.

All nursery stock should be protected fromwind and dryness in transit. A covered box truckis best, but a heavy tarpaulin is commonly used.Especially for plants with expanded foliage be-ing held for later planting, periodic water mistingto reduce moisture stress may be beneficial.

Timing of Planting

Climatic conditions determine the appropri-ate timing for the planting of nursery stock.Only the deepest cold of winter, when the soilcannot be satisfactorily worked, should be com-pletely avoided.

Climatic conditions in spring are usuallymoist and cool, with warming soil temperatures.Woody plants naturally have a burst of rootgrowth in the spring. This is generally agreed tobe the most favorable time to plant all nurserystock. It is the only realistic time to plant bare-root plants, due to the need for bare-root stock tobe planted while still dormant.

In summer, high temperatures can cause ex-treme moisture stress on all plants. Newlyplanted stock is stressed at this time more thanestablished plants. Thus, compared to thespring, this is a less favorable planting time.However, summer can be a satisfactory plantingtime. Dependable supplemental irrigation canrelieve some of the moisture stress. B&B plants,dug properly in spring prior to leafing out, havea good chance of success in summer due to their

Figure 5. Heel in bare-root stock that you planto hold for some time before planting in a per-manent location.

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already adjusted leaf area. And most containerplants have a fully intact root system. Summerplanting is stressful, but manageable with care.

Fall can be a very good time for planting.Air temperatures are moderate while soil tem-peratures are warm, favoring root growth. Dueto lengthening nights, woody plants go through a“hardening” process in the fall with little or noabove-ground growth. Roots may continue togrow, however, and as long as there are leaves,photosynthesis can occur helping to “feed” newroot development. Container plants and ever-green B&B stock make excellent fall plantingcandidates. Deciduous B&B plants should onlybe newly dug and replanted in late fall, onceleaves have dropped.

Certain trees, considered difficult to trans-plant, should generally not be planted in fall.They are plants that re-grow roots quite slowly,or have great difficulty re-initiating root growthin the spring following digging operations orother disruptions accompanying planting. Table1 presents a list of such trees. While not impos-sible to successfully transplant in the fall, a “bestmanagement practice” to maximize success withthese species is to only plant them in the spring.

Planting Methods

Reminder: the techniques discussed hereshould be considered as “best management prac-tices” but not the only methods that can lead tosuccess in landscape plant installation.

Techniques Common to All Root Types

In loose, well-drained soil, dig the hole twotimes the width of the root spread, soil ball, orcontainer size of the plant (see planting tech-niques for less ideal sites in “Planting in Heavyor Compacted Soil” below). Dig as deep as theroot system, but not much deeper. When youhave finished planting, the tree or shrub shouldbe just as deep in the new location as in the old.Flatten the bottom of the hole and tamp it to firm

Table 1. Some slow-to-root trees that are mostlikely to survive if planted in spring._____________________________________________

Scientific Name Common Name_____________________________________________

Acer rubrum Red MapleBetula spp. BirchesCercis canadensis RedbudChamaecyparis Nootka False Cypress nootkatensisCornus florida Flowering DogwoodCrataegus spp. HawthornsKoelreuteria paniculata GoldenraintreeLiriodendron tulipifera Tulip Tree, Tulip-poplarMagnolia spp. MagnoliasNyssa sylvatica Black GumPopulus spp. PoplarsPrunus spp. Stone Fruits

(Peach, Cherry, etc.)Pyrus calleryana Callery Pear,

Including ‘Bradford’Quercus alba White OakQuercus coccinea Scarlet OakQuercus macrocarpa Bur OakQuercus phellos Willow OakQuercus robur English OakQuercus rubra Red OakSalix spp. WillowsTilia tomentosa Silver LindenZelkova serrata Japanese Zelkova________________________________________

the soil. This will prevent the plant from set-tling in deeper later. If your plant is bare-root,create a small mound in the planting hole so thebottom of the hole fits the shape of the rootsystem.

In most cases, use the same soil that cameout of the hole as backfill. Mix all soil dug fromthe hole together and break up clods. On well-drained soils, a prepared backfill mix of nativesoil (two thirds) and organic matter such as sph-agnum moss peat (one-third) may be used.However, research suggests such amended back-fill mix is of no particular benefit to plant sur-vival if regular watering is provided to the newly

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planted stock. It may not do much good, but itgenerally won’t hurt! On poorly drained sites,though, backfill amending is often harmful (see“Planting in Heavy or Compacted Soil” below)and should be avoided. For amending very lightsoils, see “Planting in Excessively Sandy orLight Soil” below.

To avoid burning roots, do not add drygranular fertilizers or fresh manure to the back-fill mix. Composted manure is acceptable. Or,you may choose to place a few fertilizer pelletsin the backfill, taking care to avoid direct rootcontact. This fertilizer will not aid transplantsurvival, but may be of benefit once the plant be-comes established.

Once the hole is dug, planting instructionsvary according to the root condition of yournursery stock.

Planting Bare-Root and Machine-BalledStock

Carefully remove the moist packing materialfrom bare-root stock and examine the roots. Cutoff damaged roots with sharp pruners. Soak plantroots in water for several minutes immediatelybefore planting, but don’t let roots stand in waterfor more than an hour.

Always protect the plant’s roots from exces-sive drying. Even while you’re digging the hole,keep roots covered with damp burlap, moist sph-agnum moss, or other material to avoid exposingroots to sun and air.

For machine-balled stock, dig the hole beforeyou remove the plastic wrap and binding twine.After you take the wrapping material off the rootball, gently loosen the organic matter surround-ing the roots to permit direct contact of roots tosoil. Be careful to keep roots intact. Plant imme-diately.

For both bare-root and machine-balledplants, be sure the plant sits at exactly the samelevel in the new hole as it did where it grew be-fore (Figure 6). Place it in the center of the hole

and carefully backfill with soil. Work the soil inand around the roots, then firm it with your hand.Continue filling the hole until it is three-fourthsfull. Gently tamp the soil with your feet, butdon’t pack the soil or break roots.

After the hole is about three-fourths full, fillit full of water and let the water drain. Thissettles the soil and eliminates air pockets aroundthe roots. Do not pack the soil after it is watered.Straighten the plant if it’s crooked, and finishfilling the hole.

Figure 7. Surface conditions to complete plant-ing operation.

To catch rain water and to make wateringeasier, form a 2- to 3-inch rim of soil in a circle abit larger than the diameter of the hole (Figure7). Prepare a fertilizer solution with a watersoluble fertilizer (20-20-20 or similar analysis) at

Figure 6. Bare root planting in well-drained soil,showing sub-surface conditions

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the label recommended rate. Fill the basin withthe fertilizer solution. Additional fertilizer maybe applied as pellets in the planting hole. Addi-tional water may be applied.

After watering, add 2- to 3-inches of barkmulch or other coarse material over the entirewatering basin. Keep all mulch away from thetrunk of the tree and the stems of shrubs. For thefirst growing season, maintain the soil rimaround the basin to catch rain or irrigation water.

Planting Balled and Burlapped StockAlways handle balled and burlapped stock by

the soil ball. Lifting by the trunk or crown of theplant tends to loosen the roots in the soil ball. Itcan damage fine roots, those that are most re-sponsible for water and mineral uptake.

Stand the plant in the prepared hole of properdepth so that the top of the soil ball is level withthe surrounding soil surface, never deeper (Fig-ure 8). For trees, be sure the root flare (the point

where the tree trunk begins to widen out into theroot spread) is level with the surrounding soilsurface. With current nursery production prac-tices, sometimes trees come from a nursery al-ready too deep in the soil ball (Figure 9). Youshould find the root flare by carefully investigat-

ing the top of the soil ball, taking care not to de-stroy the ball in the process. Then, if the rootflare is somewhat buried in the soil ball, establishcorrect planting depth based on the root flare po-sition, not the top of the soil ball. The soil ballmay appear to be planted “high,” but this is amuch better situation for long-term tree healththan if the soil ball is lower, with the tree itself istoo deep.

The soil ball of larger B&B stock (usu-ally trees) is commonly bound with a wire basketin addition to burlap and twine. The wire basketis very effective at holding the soil ball together.However, it presents a bit of a dilemma at plant-ing. A decision must be made as to the disposi-tion of the basket. It should be made with theunderstanding that the wire basket, once buriedin the planting pit or under mulch, will remainintact for many years. It will not “rust away”(oxidize) rapidly because there is a very lowlevel of oxygen in the soil.

The wire basket dilemma lies in the con-flict between the short and long-term goals of theplanting activity.

On the one hand, the chance of plant sur-vival is maximized if the soil ball is kept com-pletely intact throughout the planting process. Al-lowing the wire basket to remain on the soil ballwithout any alteration will help accomplish thisshort-term goal of transplant survival.

Figure 8. Balled and burlapped planting in well-drained soil.

Figure 9. Procedure if tree is too deep in soil ball.

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On the other hand, research suggests thatwire baskets left around planted root systems,while very unlikely to be fatal, can inhibit nor-mal growth of a small percentage of roots thatcome in contact with the wire in a nearly parallelorientation or at an sharply oblique angle. Theresult may be a less vigorous plant, compared toan identical one in an identical situation withoutthe wire basket. Thus, the long term goal ofplant growth argues for basket removal.

So what is the “best practice?” Logicsuggests one must focus on the short term, that istransplant survival, first. Thus, in the judgementof the plantsman, if there is any chance the soilball would come apart if the wire basket were re-moved, it should remain in place. Conversely,complete basket removal is preferred if, in theplantsman’s judgement, there is very little likeli-hood the soil ball will come apart. This might bethe case for soil balls of very heavy soil type, orthose that have had a minimum of previous han-dling (Figure 10).

Any wire near the top of a soil ball maypose the threat of trunk girdling. At a minimum,the top loops and top wire of a wire basketshould be bent down and away from the crown,or root flare, of the plant. Better yet, they can becut off and removed from the planting hole whileleaving the bottom of the basket intact.

Backfill the hole three-fourths full. Cut alltwine or wire away from the top of the soil balland the trunk. Roll back the burlap to below thefinal soil surface. (Note: if the “burlap” is madeof plastic, you must completely remove it.) Fillthe hole with water to settle the backfill. Finishby filling the hole, but do not pack or tamp thissoil. Finally, prepare a basin, mulch and fertilizeas described for a bare-root plant (Figure 7).

Planting Containerized StockDig the hole before you remove the con-

tainer. Also, thoroughly water the containerizedplant.

You must remove metal or plastic containerscompletely. Plants likely have been in those con-tainers for a full growing season (usually CGplants) and have a dense root ball. Turn the con-tainer upside-down and give the rim a sharp tapon a hard edge. The root ball should fall out inone piece. If it does not, it may be necessary tocut the sides of the container to allow plant re-moval.

Before you put the root ball in the preparedhole, cut any long roots that completely encirclethe root ball (Figure 11). Gently pull other rootsaway from the ball and spread them out. Thiswill allow you to place backfill soil directlyaround those roots. Finish planting, mulching,and fertilizing as described for B&B stock.

The root ball of plants in papier-mache orother degradable containers (usually Potted or FPplants) will be loose, because the plant has beenin the pot for less than a full growing season.The soil probably will fall away from the roots if

Figure 11. Container grown plant handling.

Figure 10. Procedure for planting B&B stockwith wire basket.

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you take them out of the pot. Instead, positionthe pot in the prepared hole at the correct depth(Figure 12). Tear or cut away any part of the potthat extends above the final soil line. Use a sharputility knife to slash the pot vertically from bot-tom to top in five or six places. This will allowwater to penetrate into the fibers of the pot walland begin its breakdown. Backfill immediatelywhile the form of the pot and soil ball are undis-turbed. Complete the job by mulching, fertilizingand watering as described previously.

Planting in Heavy or Compacted SoilIf you want plants to survive in heavy clay

soil or soil that is hard and compacted from con-struction activities, you must select plants thatcan tolerate poor drainage conditions. You won’thave as many plant species to choose from, but ifyou choose well-adapted plants they will have amuch greater likelihood of survival. Some plantsare notoriously intolerant of poorly drained soilsand should be completely avoided (Table 2).

Dig the planting hole as wide as you have theambition to do, but at least two times the diam-eter of the root ball or spread. Some authoritiesrecommend a planting hole in compacted soilthree times the root spread in diameter. This isusually, practically speaking, unrealistic. How-ever, remember that you are basically looseningthe surrounding compacted soil for better hori-zontal root growth. Thus, this is truly a case of“if a little (width) is good, more (wider) is bet-ter.” Hole depth should be as described above,unless digging deeper allows you to breakthrough a compacted soil layer and significantlyimprove drainage. If you do dig down to break

through a hard pan layer, be sure the soil that endsup directly under the plant is firmed enough toavoid excess plant settling following planting.

Use only the soil from the hole as backfill.You may be tempted to backfill with looser soil ora lighter, amended soil mix. Don’t do it! If youdo, you likely will create a water-holding bowl,commonly called the “bathtub effect.” The lightbackfill readily allows rainfall or irrigation waterinto the hole, but the surrounding heavy or com-pacted soil only slowly allows water to drainaway from the hole. Voila, a bathtub! Too muchwater suffocates roots and kills plants.

If you absolutely must plant species of smallornamental trees or shrubs that require excellentdrainage in poorly drained soils, create a raisedbed for them. Plan for a bed at least 6- to 8-incheshigh and at least 4 feet wide for a shrub or 8 to 10feet wide for a small ornamental tree. To build araised bed, rototill or hand spade the existing soil.Then place a 3- to 4-inch layer of well-drainedsoil on top (Figure 13). Spade or rototill the addedsoil in place. Follow with a second 3- to 4-inch

Table 2. Some commonly used landscape plantsthat do not tolerate wet soils._________________________________________

Scientific Name Common Name_________________________________________

Abies concolor White FirAcer saccharum Sugar MapleCercidiphyllum japonicum Katsura treeCladrastis lutea YellowwoodCornus florida Flowering DogwoodFagus spp. BeechesHedera helix English IvyPinus strobus White PineQuercus rubra Red OakRhododendron sp. Rhododendrons,

AzaleasTaxus sp. YewsTilia cordata Littleleaf LindenTsuga canadensis Canada HemlockVinca minor Myrtle__________________________________________Figure 12. Degradable container planting.

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layer of soil and a final pass with the rototiller.You may choose to build a wall around theraised bed to prevent the soil from eroding away;however, where space permits, slope the bed’souter edges to the original level of the soil.

Figure 13. Raised bed planting for poorlydrained sites.

Planting in Excessively Sandy or Light SoilFor extremely sandy soil and if regular irri-

gation is not certain, prepare a better water-hold-ing backfill mixture. A mix of one third sphag-num moss peat and two thirds native soil is com-monly used, but proportions may vary (Figure14). You may dig the hole wider than the mini-mum, but, as always, set the plant no deeper thanit had originally been growing. Backfill with theprepared mix and add a 2 to 3-inch layer of

mulch over the planting hole. DO NOT allowthe mulch to lay against the plant stem. Be sureto apply water-soluble fertilizer at planting andagain once or twice during the first season. Ifregular irrigation is expected, research suggestsplant survival does not increase due to soilamending. But in this case, it won’t harm any-thing and may be considered “cheap insurance”against an interruption in irrigation.

Planting Under Extreme EnvironmentalConditions

Transporting and/or planting landscapeplants under conditions of extreme heat and dry-ness, especially in combination with windy con-ditions, can cause extreme moisture stress on theplants. While in transit, plants should always becovered. Periodic water misting of foliage canhelp reduce the immediate stress on plants. Ex-perience suggests the periodic sprays may im-prove transplant performance and/or survival.

After You Plant

PruningPlanting time is excellent for pruning off dis-

eased or damaged branches, basal (sucker)shoots, and tree limbs with extremely narrowcrotch angles. For shade trees, you can take thistime to select major scaffold limbs to retain, thenprune out excess branches.

Research suggests that shoot pruning specifi-cally to “balance” roots and shoots is not desir-able at planting. Container trees retain intactroot systems so the root-shoot balance is main-tained. B&B nursery stock, dug at the propertime in early spring prior to leafing out, gener-ally compensates for reduced root mass in thesoil ball by producing smaller leaves the firstyear. The leaves on newly planted trees are im-portant for photosynthesis. They produce the“fuel” that supports new root growth followingplanting. Only under the most extreme condi-tions of hot summer planting without irrigationshould pruning be done to balance roots andshoots.

Figure 14. Optional backfill amending whenplanting in very sandy soil.

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Staking and GuyingTo keep trees from tipping due to “wind

throw” before new root growth has adequatelyanchored them, stake and guy bare-root treeslarger than 6-feet tall, and balled and burlappedtrees 8 to 10-feet tall or larger (Figure 15). Smalltrees usually don’t need the support.

Drive stakes into undisturbed ground adjacentto the planting hole, but 1 - 2 feet away. This willprovide firm anchorage and avoid damage to theroots of the newly planted stock. For guys, usefabric mesh bands specifically made for tree sup-port. Attach the bands to the three stakes and tothe lowest whorl of scaffold limbs in the tree.Loop the bands around the tree limbs; don’t tiethem tight. Guys should be taut, but still allowfor some minimal sway of the tree trunk.

Don’t forget to remove the stakes and guys ina timely manner. Generally, remove supports afterone growing season for a 1 to 2-inch diametertree. For larger trees, guys may need to remainfor two seasons or more. They should be in-spected regularly, adjusted as needed and re-moved promptly. Failure to attend to guy removalcan be injurious, or fatal, to landscape trees.

Trunk WrappingWrap the trunks of newly planted trees, espe-

cially thin-barked trees like red maple, with alight-colored, commercially available tree wrapin the late fall for winter protection from sun-scald. Remove the wrapping material in spring.Wrap trees each fall until the bark is rough andcorky, which may not occur for several years fol-lowing planting.

Start the wrap at the base of the tree, and ex-tend it to the first limb. Spiral the wrap aroundthe trunk with each turn overlapping the previousturn by half the width of the material. Secure thewrap with an expandable, flexible tape, twine, orby looping it back on itself.

For small trees, you may want to protect thelower part of the trunk with wire or plasticguards. This will discourage rabbits and rodentsfrom feeding on the bark in winter.

IrrigationWatering, in correct amounts at proper timing,

is critical to landscape transplant survival. Over-watering is just as harmful as underwatering.How often and how much you water dependsupon your soil type and the amount of rainfall.All irrigation recommendations are based on theassumption that there is no natural rainfall andshould be adjusted accordingly for rainfall events.

On well-drained soils, during the first monthfollowing planting, apply 1 inch of water every 4-5 days. After the first month, apply 1 inch perweek through the summer and fall. On sandysoils, give plants at least 2 inches of water every4-5 days at first, then per week. Plants in poorlydrained, clay soils need less irrigation water be-cause the soil tends to hold water longer.

Don’t water a little every day. Waterthorougly, then refrain from applying water forthe recommended interval of days. This approachprovides adequate moisture, but also allows rootsto get enough air. Both are essential. A little wa-ter every day or every other day excludes air andcan cause root death.

Figure 15. Stake and wrap large trees.

Fabricwebbing orwire

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Optimizing Transplanting Within aLandscape

Moving a small tree or shrub from one spotto another in a landscape is best done with lots oflead time. Two years before the move, startpruning roots in early fall while trees are stillgrowing. This gives the plant the best chance forsurvival following the move. If you don’t root-prune the plant before the move, it may still sur-vive, but the chances of success are reduced.

To prune roots of small trees, first measurethe trunk diameter at your waist height. Then,measure out 9 inches from the trunk for eachinch of diameter. For example, a tree with a di-ameter of 1-1/2 inches should be root pruned 13-1/2 inches from the trunk. For shrubs, make theroot-pruning cut half the distance of the radius ofthe branch spread of the shrub. For example, ashrub with a spread of 36 inches from the centerto the outer-most branches should be root prunedat 18 inches from the center.

When plants are dormant, cut straight downthrough the soil around two quarters of the planton two opposite sides (Figure 16). Use a sharp

spade to cut 18 inches deep. During the dormantseason the second year, cut around the remainingtwo quarters of the perimeter of the dormantplant. This two-year process cuts off many longroots and encourages new roots to grow closer tothe plant stem. Move the plant during the thirddormant season.

When you’re ready to move a plant, tie thebranches to the central trunk to minimize thewidth of the plant. Then start digging 6 inchesfurther away from the trunk than the root-pruningline. Dig a circular trench 18 inches deep. Whenthe circular hole is completely finished, push theshovel blade beneath the root ball. This will cutany deeper roots. Then, gently rock the plant(with the soil ball attached) from side to sidewhile cutting the roots on the bottom of the soilball. Finally, slide burlap under the ball.

Grasp all four corners of the burlap, and liftthe soil ball out of the hole. Wrap the burlaptightly around the soil ball. Tie the burlap so itcannot get loose in handling. Handle the plantcarefully, by lifting the soil ball, not the trunk. Donot break the soil ball! Plant as described above.

Figure 16. Before digging and moving a tree or shrub, root-prune for two years and transplantduring the third.

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Fertilizing Landscape Plants

Proper fertilization results in vigorous treeand shrub growth with attractive foliage and in-creased disease and pest resistance. Growth ratewill vary somewhat among different species andfrom season to season, but generally, young,healthy trees produce 9 to 12 inches or more ofterminal growth per year. Mature trees usuallyaverage 6 to 9 inches of annual growth. Theamount of growth for the current year can bemeasured from the tip of the twig to the first ringof bud scale scars; for previous years, the dis-tance between one ring of bud scale scars and thenext ring measures growth. Growth rate for anindividual tree can be determined by comparingthe growth of several seasons.

Fertilizing can quicken growth of youngplants and can help stimulate growth of slow-growing species. Under proper nutritional care,even the so-called slow-growing trees may growas rapidly as many other species. Although ma-ture trees and shrubs that have reached full sizeneed less fertilizing than young specimens, regu-lar light fertilizing will maintain good color andhealth while limiting excessive growth.

When nutrients are the primary reason forfertilizer application (rather than soil structuralimprovement), inorganic fertilizers are preferred.They cost less per unit of nutrient, containgreater percentages of a given nutrient, and areeasier to handle and apply because they are moreconcentrated and less bulky. The nutrients aremore quickly available to the plants and are notdependent on the rate of organic decomposition,which, in turn, is dependent on temperature,moisture, and soil composition. A comprehen-sive presentation of the types and forms of fertil-izers is found in Chapter 5, Soils and Plant Nu-trition.

If trees and shrubs are growing in a lawnwhere a complete fertilizer program is followedto promote healthy turf, the woody plants prob-ably will not need additional fertilizer. If grown

in beds, however, the woody plants should befertilized as described below. Note that fertil-izer-herbicide mixes (“weed and feed”) designedfor turf should never be used in plant beds. Ingeneral, turf herbicides such as 2,4-D anddicamba should not be used over the roots oftrees or shrubs because they may enter the plantsthough the root system and cause damage. Dam-age can include disfiguring of new growth, die-back of twigs and branches, and, in severe cases,death of the plants.

A soil test should be used to determine pHand whether or not adequate levels of phospho-rus (P) and potassium (K) are present in the soil.Usually for woody ornamental plants, nitrogen(N) is the nutrient in short supply. All three, plusother elements in less amounts, are necessary forhealthy plants, but nitrogen (N) leaches out ofthe root zone and must be replaced annually.Rarely are all three elements deficient in thesame soil.

Generally, an application of phosphorus (P)and potassium (K) every three to five years is ad-equate for satisfactory growth of woody plants.Phosphorus (P) forms relatively insoluble com-pounds in the soil and becomes available slowlythrough several growing seasons. Potassium (K)is available in the soil as an exchangeable ion.

Nitrogen (N) should be applied as required tomaintain green leaves and vigorous growth. Forrapidly growing plants, an annual application ispreferred to ensure adequate amounts, while inpoor, sandy soils, which do not hold fertilizerswell, it may be necessary to make more frequentapplications.

If a soil test shows that P and K are at low ormedium levels, use a fertilizer mix such as 10-10-10, 16-8-8, or 20-10-5. If the soil is high in Pand K, use a straight N fertilizer such as 21-0-0,33-0-0, or 45-0-0.

Rates of ApplicationA fertilizer program for trees and shrubs

needs to maintain a fertility level that will pro-

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vide nutrients as required during the growth ofthe plant. Calculate the size of the planting bedor lawn area containing the woody plants. Fertil-izer should be applied to the feeder root zone ofshrubs and trees. For shrubs, consider either theentire bed area, or an area twice the diameter ofthe shrub, as the feeder root zone. Tree feederroots occur in an area below and on either side ofthe dripline of the tree canopy (end of branchspread). To calculate an appropriate area to fertil-ize, include the area from one-half the canopy ra-dius from the trunk extending to one-half thecanopy radius beyond the dripline. For severaltrees in a yard, calculate the entire yard as thetree root zone. A rate of 2 to 4 pounds of N per1000 square feet of soil per year is consideredoptimal. To reduce the risk of fertilizer injury,this total amount may be divided into two ormore portions and used in two or more applica-tions during the growing season. Even if appliedall at one time, a nitrogen treatment of 4 pounds/1000 square feet is not considered excessive forwell-established plantings in beds. For plantsgrowing in turf, however, split applicationsshould be used to avoid damage to the turf.

If four pounds of N are to be applied annu-ally, apply 2 pounds of nitrogen per 1000 squarefeet in spring before growth begins, or just asbuds are swelling, and 2 more pounds per 1000square feet in fall about the time of leaf drop orthe first killing frost. If only 2 pounds of N willbe applied per year, make a single application inthe fall.

As long as soil temperatures are above 40°F,roots can absorb nutrients (Table 3). Both springand fall are active periods of root growth. Anadded advantage is that in spring and mid-fall,soil moisture conditions favor plant nutrient up-take.

If desired, quick-release nitrogen may be ap-plied in late spring. Avoid fertilizing duringmid-summer. The late season growth stimulatedby such treatments may be injured by fall andwinter cold snaps in some areas.

Table 3. Spring and fall soil temperatures (°F) at4” depth, Tippecanoe Co., IN, average over 18-year period.________________________________________________

Under Bare Soil Under Turf_________________________________________________Spring

March 15 38.1 38.222 41.1 41.129 43.9 43.7

April 5 46.7 46.112 49.4 48.719 52.2 51.126 55.0 53.7

FallOct. 20 55.1 55.6

27 52.5 53.4Nov. 3 49.9 51.2

10 47.2 49.117 44.5 46.924 41.9 44.7

Dec. 1 39.3 42.58 36.5 40.3

__________________________________________

To calculate the amount of fertilizer needed tosupply 2 pounds of nitrogen per 1000 square feet,use the percent nitrogen figure in the fertilizeranalysis. N is the first number of the three num-bers in a fertilizer analysis. If the fertilizer has a10-6-4 analysis, a 50-pound bag contains 5pounds of nitrogen (10% of 50 lb. = 5 lb.). Ap-plied at a rate of 20 pounds of fertilizer (2 lb. ac-tual N) per 1000 square feet, the 50-pound bagwill cover 2500 square feet. Stated another way,for 1000 square feet, use 20 pounds of 10-6-4 fer-tilizer, or, for smaller beds, apply 2 pounds for ev-ery 100 square feet. Table 4 gives rates for apply-ing some common fertilizers.

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Table 4. Amount of nitrogen fertilizers neededto supply 4, 2, and 1 lb. of actual nitrogen per1000 square feet.________________________________________

Fertilizer Approx. lb. ofProduct fertilizer needed____________________________________________

4 lb N 2 lb N 1 lb NUrea (45-0-0) 9 4.5 2.2Ammonium nitrate (33-0-0) 12 6 3Ammonium sulfate (21-0-0) 20 10 510-10-10 40 20 1012-12-12 33 16.7 8.3______________________________________________

To re-emphasize a point made earlier, oncewoody plants have reached their desired size,little fertilizing is needed.

Caution: Too heavy a rate of application canlead to weak excessive growth or to damagedplant tissue, including the roots. A damaged rootsystem can result in deficiency of nutrientswithin the plant, even when soil nutrient levelsare adequate.

If injury from fertilizer salts occurs, two ormore heavy waterings may leach excess saltsfrom the soil. Gypsum worked in to the soilprior to the irrigation may aid in displacing ex-cess fertilizer salt ions.

Keeping plants well watered during thegrowing season after fertilizer application willhelp prevent injury. If rainfall is sparse or infre-quent, supplementary thorough watering will bebeneficial. Use of a slow-release fertilizer prod-uct is another safeguard against the possibility ofinjury. This type of N breaks down graduallyover a period of several months and suppliesplants with an even amount during this period.Its disadvantage is its higher cost, which may notbe justified due to the fact that many trees and

shrubs only grow in one flush per year, so a con-tinuous nutrient supply is not needed. Use ofslow-release products at less than recommendedrates gives poor results because insufficient N isavailable at any given time for plant needs.

Calculating fertilizer amounts on the basis ofsize of the bed or spread of the tree (see next sec-tion) is preferred over basing amounts on thetrunk diameter of the plant.

Methods of ApplicationFertilizers are available in granular or pelleted

forms for dry application and in water-soluble orliquid forms that can be applied with a hose orsprayer.

Dry fertilizers may be broadcast by hand orspread by drop-type or rotary distributors. Figure17 illustrates both rotary- and drop-type spread-ers. Avoid uneven distribution by dividing thefertilizer to be applied in half, then applying one-half lengthwise over the area, the remaindercrosswise over the area. If isolated trees within alawn are being fertilized, the turf will be stimu-lated by the treatment and will be greener andfaster growing than untreated areas. This so-called “oasis effect” can be avoided by extendingthe fertilizer treatment beyond the area the treescover. Water the area thoroughly after application

Figure 17. Rotary and drop-type spreaders areuseful for dry fertilizer distribution.

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to remove the fertilizer from grass or groundcover and move it down into the soil.

Since nitrogen moves through the soilreadily, surface application as described above issuitable if only N is being applied. If soil testsindicate a need for either phosphorus or potas-sium, placing the nutrients in holes in the rootzone of the trees is preferred (Table 5). Fertilizerin holes 1 or 2 inches in diameter and 12 to 18inches deep will reach many of the feeder rootsof trees. Feeder roots of most trees are abundantin the top 12” – 18” of most soils.

Table 5. Amounts of phosphorus (P) and potas-sium (K) fertilizer materials needed to supplyapproximately 3.6 lbs P2O5 per 1000 sq ft and/or 6 lbs of K2O per 1000 sq ft._____________________________________________

Amount/hole based on 250

Quantity holes/1000 sq ftFertilizer needed/ (holes on 2 ftProduct 1000 sq ft grid)_____________________________________________

Phosphorus (P) 18 lb 2 tsp superphosphate (0-20-0)Treble super 8 lb 1 tbsp phosphate (0-46-0)Potassium muriate 10 lb. 1 tbsp. of potash (0-0-60)12-12-12* 30 lb. 1/2 cup *This supplies full phosphorus, but only half potassium rate.______________________________________________

Holes may be punched in the soil with a steelbar or drilled with an auger attached to an elec-tric drill. The latter method is preferred in heavysoils since it does not compact the sides of theholes and permits dissolved fertilizer to movemore freely from the hole. Such drilling has theadded bonus of improving aeration in heavysoils. When the added fertilizer is combined withorganic-matter backfill, the hole drilling and fill-ing process is known as “vertical mulching.”

Figure 18. Placing fertilizer in holes, evenlyspaced in the root zone of the tree, is recom-mended for potassium and phosphorus.

Space holes 2 feet apart in a rectangular pat-tern beneath and somewhat beyond the spread ofthe branches (Figure 18). Do not drill holeswithin 2 feet of the trunk of trees with a 12-inchtrunk diameter or within 3 feet of trees with an18-inch diameter. The required amount of fertil-izer, based on the area to be covered and rate ofapplication, should be divided equally to fill thenumber of holes, and can be applied with a funnelor a can with the top edge bent to form a pouringspout. After the fertilizer has been added, waterthoroughly. The holes then may be filled withsand, topsoil, or organic matter.

So-called “tree spikes” that are driven into theground at intervals beneath and around trees andshrubs may be used as an alternative to drillingand filling holes, but they are more expensivethan the method described above.

Other methods of application are a) injectionof liquid fertilizer below the ground, using a spe-cial injector wand and water pressure to force thesolution into the soil; b) application of liquid fer-tilizer to the foliage of the plant; and c) injectionof nutrients into the tree trunk, using specialequipment. The latter two methods are usuallyreserved for treating deficiencies of specific mi-cro-nutrients such as iron or manganese. Foliagetreatment and trunk injection give quick results,

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but are more costly and less long-lasting than nu-trients applied to the root zone of the plants. Fo-liar feeding of small and medium-sized shrubsmay be done by the homeowner; proper cover-age of trees and large shrubs will require the ser-vices of a professional arborist. Injection meth-ods will also call for employment of a profes-sional; often equipment available to home own-ers will not supply an adequate amount of fertil-izer.

Special Cases

Deciduous TreesMature trees need little fertilization as long

as they have good leaf color and grow reason-ably well. Stimulating increased growth may in-crease foliage density to the point that interiorfoliage and plants growing beneath the trees maybe weakened by heavy shade.

For trees growing in confined areas whereroots are restricted by pavement, buildings, orother construction, fertilizer rates should bebased on the area in which the roots are confinedand not upon the branch spread when using thesteel bar or auger method. Applying too heavy arate will result in root damage.

Trees with very narrow crowns (i.e. very nar-rowly columnar cultivars) will have a broaderroot spread than crown spread. Fertilizer shouldbe applied beyond the canopy spread, up to threetimes the distance of the dripline.

Deciduous ShrubsSurface application is preferred to in-hole

placement for small or shallow-rooted shrubs.Fertilizer should be scattered evenly beneath theshrub and beyond, to double the shrub diameter,or applied to the entire bed if plants are close to-gether. Care should be taken to avoid contactbetween the stems or trunks of plants and the fer-tilizer, and application should be followed with athorough watering. If the shrubs are known tobe deep rooted, the fertilizer may be worked intothe soil.

While plants are small and rapid growth isdesired, higher rates of nutrients can be applied.As plants reached desired size, reduce or elimi-nate fertilizer to limit growth.

Newly Planted Trees and ShrubsDamage to roots (“root burn”) can occur

when inorganic fertilizer is incorporated intobackfill soil used in planting. Surface applica-tion of a water-soluble fertilizer, watered in well,is preferred. Many people avoid using any fertil-izer during the planting year as research suggestsinitial root growth depends mostly on stored nu-trients in the plant and on photosynthesis. Slow-release fertilizers or fertilizer pellets carefullyplaced in the planting hole well away from rootsmay pay future dividends as the roots expand.

Coniferous and Broadleaf EvergreensEvergreen trees and shrubs require lower

rates of nutrients than their deciduous counter-parts. Over-fertilizing conifer trees leads to opengrowth with widely spaced branches. Narrow-leaved evergreen shrubs generally need onlyabout one-half the fertilizer of deciduous plantsto maintain good foliage color, especially if usedin small scale plantings.

Many broadleaved evergreens have shallowroot systems which are easily burned by highlyconcentrated chemical fertilizers. These plantsneed an acid soil pH for efficient nutrient uptake.Most landscape suppliers carry special acid-based fertilizers formulated for broadleaved ev-ergreens. These fertilizers contain both an inor-ganic source of acid-type nitrogen, which isquickly available to a plant, and an organicsource, which will supply N over a period oftime. Lime, wood ashes, or bone meal will raisethe soil pH and should be avoided. The punchbarmethod of fertilizer application should not beused with broadleaved evergreens, nor shouldsurface applications be worked into the soil. Anacid-type organic mulch, such as sphagnummoss peat or rotted oak-leaf mold, will help con-serve moisture, keep weeds down, and protectthe roots from excessive summer heat.

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Pruning Landscape Plants

Correct pruning is an essential maintenancepractice for landscape trees and shrubs. However,many workers regard pruning with considerable,though unnecessary, apprehension. Pruning is notdifficult if you understand the basics; learn why,when, and how to prune.

Trees and shrubs should be examined annu-ally for pruning requirements. Too often, pruningis ignored for several years. Then some trees andmost shrubs become overgrown and often weak,making drastic pruning a necessity to bring theplant back to usefulness. Regular pruning willhelp keep the plant in bounds and keep its growthvigorous. To prune successfully, you must 1)know why you are pruning, 2) be correct in yourtiming, and 3) follow proper techniques usingproper tools: why, when, and how.

Reasons to PrunePruning is usually necessary to maintain a

successfully functional landscape tree or shrub.Specifically, pruning is practiced to:

Maintain or reduce plant size. Pruning canprevent a plant from overgrowing its space in thelandscape and eliminates the need for drastic cut-ting of crowded, overgrown plants. It can allowfor growth of other plants underneath or adjacentto the pruned plant.

Remove undesirable growth. Pruning canencourage plant vigor through the removal ofweak, overcrowded growth. Such thinning oftenimproves the visual balance or symmetry of theplant.

Remove dead, diseased, or brokenbranches. Pruning will aid in maintaining theshape, vigor, and health of the plant.

Stimulate flowering and fruiting. Removalof the current year’s old, faded flowers and devel-oping fruit will promote flower buds for the fol-lowing season.

Rejuvenate and restore old plants to vigor-ous growth. Proper pruning can restore a youth-ful growth habit in certain mature and/or over-grown shrubs.

Prevent damage to life and property. Prun-ing can minimize the hazard of limbs interfering

with power lines or hitting pedestrians. It can alsoremove limbs with weak crotches before theybreak in strong winds and open blocked sight linescaused by overhanging limbs at driveways orstreet corners.

Shape plants in an artificial form. Pruningand shearing can be used to shape plants as hedgesor for rigidly formal espaliers or topiaries.

Myths About Pruning

There are a number of myths and misconcep-tions about pruning which should be laid to rest.

Pruning is difficult. Pruning is straightfor-ward if one knows a little about how the plantgrows and what it should look like when the pro-cess is complete.

Plants will die if pruned at the wrong timeof year. Plants may be injured, but seldom, if ever,are they killed by poorly timed pruning.

All pruning must be done during the winter.Actually, many plants are best pruned during thegrowing season.

Topping shade trees will keep the trees fromcausing damage to the home. Shoots which growafter topping are weaker than the original limbs.They will be more likely to split off and causedamage unless they are removed every few years.Also, wood rots are more likely to be a problem intopped trees, resulting in poorer tree health andgreater likelihood of limb breakage.

Removing a tree is a crime against nature. Ifa plant is in the wrong place, from a functional oraesthetic viewpoint, it is by definition a weed andcan be removed. This is especially true when a treemust be mutilated beyond recognition to eliminatethe problem it is causing.

Most trees need pruning. Actually, mature treesseldom do. Young trees usually benefit because prun-ing helps in establishing the basic branch structure.

Hedge shears are all you need to prune shrubs.Hedge shears are intended to prune hedges, only!Using them on shrubs not intended as hedge plantsdestroys the natural grace and beauty of the plants.

All cut surfaces must be treated with treepaint. While long recommended, the evidence iscontrary to the use of tree paint. Its use should bethought of as only cosmetic, helping to hide light-colored scars.

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Times to Prune for Specific PurposesTiming of pruning is based on the flowering,

fruiting, or growth habits of a plant, its tendencyto “bleed,” and the fact that pruning usually stimu-lates a flush of re-growth. Most plants can bepruned at almost any time of year without jeopar-dizing basic survival. However, it is preferable toprune specific plants at specific points in the year.

Pruning According to Season of BloomTrees and shrubs that flower before July are

best pruned immediately after flowering. Flowerbuds develop during the previous season’s growth,thus, the flowers for the current year’s bloom de-veloped last year and overwintered in the bud. Ifpruned before spring flowering, the flower budswill be removed, thus eliminating flowering. Table6 shows examples of plants which are best prunedafter flowering.

Later flowering trees and shrubs are bestpruned in late winter or early spring before newgrowth starts. These plants develop flower budsduring the spring of the flowering season. Ex-amples of plants of this type are shown in Table 7.

Certain plants can be pruned both before andafter flowering. This often increases flower andfruit production, and several may produce a sec-ond bloom during the year. Table 8 shows examplesof this plant type.

In the foregoing cases, the timing of pruning isbased on common sense to maximize flowering ofa plant which was planted for its flowers. If prun-ing is timed such that flowering is sacrificed, itwill not be harmful to the plant’s survival. It willsimply mean a loss of one season’s floral display.

Table 6. Spring-flowering trees and shrubswhich should be pruned after flowering.________________________________________

Scientific name Common name________________________________________Amelanchier ShadblowBerberis BarberryCalycanthus SweetshrubCaragana PeashrubCelastrus BittersweetCercis RedbudChaenomeles Flowering QuinceChionanthus FringetreeCornus florida Flowering DogwoodCornus kousa Kousa DogwoodCornus mas CorneliancherryCotinus coggygria SmoketreeCotoneaster CotoneasterCrataegus HawthornDeutzia DeutziaEuonymus Winged Spindle TreeForsythia ForsythiaKalmia latifolia Mountain LaurelKolkwitzia amabilis BeautybushLaburnum LaburnumLigustrum PrivetLindera SpicebushLonicera HoneysuckleMagnolia MagnoliaMalus CrabapplePhiladelphus MockorangePieris AndromedaPrunus Flowering Cherry

and PlumPyracantha FirethornRhododendron Rhododendron and

AzaleaRhodotypos scandens Black JetbeadRibes CurrantRosa Climbers and Shrub

RosesSorbus Mountain AshSpiraea thunbergii Thunberg SpireaSpiraea x vanhouttei Vanhoutte SpireaStyrax japonica Japanese SnowbellSyringa LilacViburnum ViburnumWeigela WeigelaWisteria Wisteria________________________________________________

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Table 7. Summer-flowering trees and shrubswhich should be pruned before spring growthbegins.________________________________________________

Scientific name Common name________________________________________________

Abelia x grandiflora Glossy AbeliaAcanthopanax AraliaAlbizia julibrissin Silk TreeBuddleia davidii ButterflybushCallicarpa BeautyberryHibiscus syriacus Rose of SharonHydrangea arborescens Smooth HydrangeaHydrangea paniculata Pee Gee Hydrangea

‘Grandiflora’Hypericum St. JohnswortKoelreuteria paniculata Goldenrain TreeMagnolia virginiana Sweet BayRhus SumacRosa cvs. Hybrid Tea RosesSorbaria False-spireaStewartia StewartiaSymphoricarpos Snowberry, Coral-

berry________________________________________________

Table 8. Trees and shrubs which may be prunedboth before and after bloom.________________________________________________

Scientific name Common name________________________________________________

Cornus sericea Red-osier DogwoodCotoneaster apiculatus Cranberry CotoneasterCotoneaster divaricatus Spreading CotoneasterCotoneaster multiflorus Many-flowered Coto-

neasterMahonia aquifolium Oregon GrapehollySpiraea x bumalda Anthony Waterer and

Froebel SpireaSpiraea japonica Japanese SpireaSymphoricarpos albus SnowberrySymphoricarpos x chenaultii Chenault CoralberryWeigela Weigela________________________________________________

Pruning to Maximize Fruiting DisplayShrubs or trees that are prized for their fruit

should be pruned after the fruit drops or is eatenby wildlife. Although they may flower early inthe season, the fruit should be allowed to de-velop. After the fruit has lost its appeal, thenprune. Examples of plants in this group are cer-tain viburnums and hawthorns.

Pruning Needle (Coniferous) EvergreensTo promote a compact plant, coniferous ever-

greens can be pruned in late spring as the newbranches elongate, but before they become stiff.Otherwise, they, like broadleaved evergreens,can be pruned whenever the wood is not frozen.However, coniferous types will generally not de-velop new shoots on older wood, so don’t cutback beyond the living foliage portion of thebranches.

Pruning Trees Known as “Bleeders”Some deciduous trees have an exceptionally

heavy sap flow in the early spring. If cuts aremade then, the trees will “bleed.” While this saploss does not injure the tree, it can be objection-able aesthetically and cause problems for pedes-trians, automobiles, etc., passing underneath.“Bleeding” can be avoided by pruning in mid-summer or late fall. Maple, birch, dogwood, elm,walnut, and yellowwood are examples of“bleeder” trees.

Pruning in Anticipation of GrowthStimulation

In general, except for the cases already cited,the best time to prune is when the plant will re-cover the fastest. Severe pruning should be donejust before regrowth starts in the spring so cutswill be hidden quickly. Heavy pruning in latesummer should be avoided. It stimulates succu-lent growth which may not harden sufficiently toavoid winter dieback. Storm-damaged plantsshould be pruned immediately after the damageoccurs.

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Tools for PruningProper pruning requires proper tools, em-

ploying correct methods, and correct applicationof the methods. Tools should be of the highestquality you can afford, and they should be sharp.Keep them in good condition by lubricatingregularly, cleaning to prevent rust, and only us-ing them for their intended function. (See Figure19 for examples of common pruning tools.)

Basic Procedures in PruningThere are two basic techniques at the heart of

all pruning situations: heading back and thin-ning.

Heading back (Figure 20) shortens a stem orbranch. A cut is made some distance behind thebranch tip at a point just above a bud or lateralbranch. A proper cut should not leave a stub.An angle cut is best. Make the cut about 1/4”above the bud or branch.

A specific type of heading back is pinching(Figure 21). It is generally done by hand, with-out shears, and is done only on the currentseason’s shoot growth when it is still soft and

Figure 20. Heading back for size control andproper cuts.

Figure 19. Examples of common pruning tools.-

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succulent. It’s a good way to slow down growthand control plant size. It is also useful to in-crease the shoot density in a plant.

Thinning completely removes a branch orstem. The cut is made at the point of origin ofthe stem; that is at a larger branch, the tree trunkor the soil line. A proper thinning cut does notleave a long stump. More importantly, a thin-ning cut should never cut into or remove the“branch collar” (Figure 22).

The branch collar is a zone of wood at thebase of a branch where the branch attaches to alarger stem or the tree trunk. The branch collaris usually recognizable as an enlarged area, oftenwith the bark having a distinctly different surfacetexture and/or color. It may be a few up to sev-eral inches long. The branch collar is importantbecause it contains plant cells that function as abarrier preventing fungi and bacteria from suc-cessfully penetrating into the interior of thebranch or trunk that remains as part of thepruned plant. Branch collar protection decreasesthe likelihood of heart rot and probably helps ex-tend the useful life of any tree that has had limbsremoved by pruning. Always make a thinningcut at the outer edge of the branch collar zone!

The Wound Dressing QuestionWound dressing or tree paint is not essential,

or desirable, for plant health. Dressings may ac-tually harbor disease organisms rather than ex-clude them. Wound dressing slows wound cal-lusing (the growth of a corky ridge around theedge of a pruning cut, often called “healing”)which is responsible for wound closure. The

only reason for painting a pruning cut is a cos-metic one. When appearance is a factor, thepainting should be done with latex paint. Neveruse oil paint! On the basis of tree health alone,pruning cuts should not be painted or dressed.

Basic Safety Rules for Pruning

1. Only do pruning work, especially on largetrees, with proper equipment.

2. Keep all equipment sharp and in good repair.3. Use a piece of equipment only for the job it

was designed to do.4. Be conscious of electric lines when pruning

near them.5. If a power line is touching a tree limb, call

the power company promptly and stay clearof the tree.

6. Never climb a tree without using a safetyrope, with or without a ladder.

7. Keep your fingers clear when using handclippers.

8. Use care in handling pruned limbs and brushto avoid eye injury.

Figure 22. Thinning of limbs back to a maintrunk and a proper cut.

Figure 21. Pinching out growing tips of shoots.

(Don’t)

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Procedures for Pruning Specific Trees andShrubs

Deciduous Shrubs and TreesGenerally, allow a shrub or tree to develop its

natural shape, except when special effects are de-sirable, such as for hedges. “Haircut” pruningshould be avoided (Figure 23). Perfectly shearedglobes and squares aren’t appropriate except inextremely formal landscapes.

Instead, use thinning and heading back tech-niques on both shrubs and trees. Cut backbranches at different lengths, 1/4" above an ac-tive bud. Remove twigs or branches selectivelyand thus reduce overcrowding. Some stemsshould also be removed at ground level. Thelength of new shoots should be reduced 1/3 to1/2 of their length, which allows side shoots todevelop.

Cutting above a bud prevents dieback of thestem and encourages a new branch to developfrom the bud. The haircut technique causes adense growth at the ends of the pruned brancheswhich shades the rest of the plant, thus causingthe plant to eventually develop a leggy appear-ance. If a shrub develops a weak, dense growth,thin out many of the smaller branches and twigs.This promotes the vigorous growth of the re-maining branches. Also remove branches whichtend to rub against one another, opening woundsfor the entrance of disease.

Always remove dead, damaged, or diseasedbranches and limbs from established plants aswell as newly planted trees and shrubs. Also, re-move dead flower branches, dead flowers, and oldfruit stocks as soon as the flowers have wilted orthe fruit has dropped. This stimulates new growthand helps to make a stronger tree or shrub. It alsoencourages plants such as rhododendrons to pro-duce more flower buds for next season.

Evergreen Shrubs and TreesWith evergreen shrubs, generally avoid shear-

ing to artificial shapes. If the evergreen plant has asoft, feathery appearance, prune to maintain thatcharacter. Use the thinning technique, thus keep-ing the natural shape of the evergreen. Remember,the non-green portion of needle-leaved evergreenbranches does not normally put out new branches.Therefore do not cut branches back to leafless oldwood (yews (Taxus) are an exception to this rule).Reduce new growth annually, and when removingthe larger branches by thinning, cut close to themain trunk, leaving no stubs. Heavy thinning isneeded only every few years.

With certain evergreens such as yews (Taxus),a new flush of growth will occur in the early fall.Head back these long shoots to keep the plants inshape.

Broadleafed evergreen shrubs are pruned inthe same manner as narrowleafed evergreens, bythinning and heading back. Light pruning everyyear is preferred, but heavy pruning every threeyears is acceptable. Rhododendron species benefitfrom removal of flower heads immediately afterflowering. Most types, such as hollies, pyracan-tha, azaleas, and euonymus, can be cut back se-verely, but avoid cutting all the way to the ground.Holly trees may be pruned at Christmas time.

To thicken the new growth of coniferous treessuch as pines, spruce, or fir, pinch out 1/2 or moreof the candle (the new shoot growth on eachbranch) when it is fully extended (Figure 24). Donot use shears, since they damage the needles thatare around the candle and cause the cut edges toturn brown. This gives the tree an unsightly

Figure 23. “Haircut” pruning should be avoided.

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appearance. Do not top or remove the centralleader if the natural, conical growth habit of thetree is desired.

If the terminal of a needle evergreen tree hasbeen lost, it is necessary to aid the plant in grow-ing a new terminal shoot. Without assistance, asingle terminal will probably not be re-estab-lished, and multiple leaders will result.

To form a new terminal, bend one of the young-est lateral branches near the terminal into an up-right position. Secure it to the dead terminalstub or insert a stake for rigidity. After a season,this branch will take over as a terminal “centralleader” shoot. Once this occurs, remove the stubor stake, and the plant will maintain its charac-teristic growth habit (Figure 25).

Figure 25. Replace a lost terminal leader by ty-ing a lateral branch in a vertical position and se-curing it to the stub of the dead terminal, or to astake secured to the main stem.

tie todeadshoot

bend lateralbranch toverticalposition

tie tostake

Figure 26. Establish alternate branching.

Figure 27. Remove branches with a narrowangle that becomes a weak crotch (a), and leavewide-angled, strong crotches (b).

Newly Transplanted TreesThe pruning of trees at the time of trans-

planting should focus on three goals. One is theimprovement of branch spacing and distribu-tion (Figure 26). The second is retention oflimbs with desirable attachment angles (Figure27). Both are accomplished by selective thin-ning of limbs in the center of the crown. Thethird is removal of competing central growingpoints (central leaders) (Figure 28).

Figure 28. Maintain a single dominant, centralleader shoot at the highest point in a shade tree.

goal: asingle centralleader

leave thismain stem

remove thiscompetingstem completely

Figure 24. Pinch needle evergreen candles whennew growth is about 2 inches long. Remove 1/2or more of the candle.

break off by hand,don’t cut withshears

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When a tree is young is the best time to es-tablish a strong interior structure of limbs thatcan bear the necessary weight as the tree ma-tures. The attachment points of major limbs tothe main trunk should alternate up the trunk sothey are widely spaced vertically. They shouldalso be widely distributed radially. This distribu-tion will mean each major limb will have enoughroom to grow and increase in diameter.

The angle of limb attachment (crotch angle)is important for strength. Crotch angles that arenarrow (generally less than 30°) become weakand are prone to failure in high winds or underice loading in winter. Crotch angles of 60° - 90°tend to be strong. Crotch angle is, to some de-gree, a genetic trait of a tree species. Some trees,such as silver maple, often develop narrowangles while others such as sycamore and whiteoak tend to produce nearly perpendicularcrotches. Prune to retain the limbs with the bestcrotch angles and to eliminate the really narrowones prone to failure.

On most shade trees, the top-most growingpoint (central leader) is critical to achieving aform typical of the species. It is seldom desir-able cut a central leader. It should be prunedonly if absolutely necessary (for height reduc-tion, because it is damaged, etc.) and then, onlywith care and knowledgeable consideration ofthe future growth of the tree. Sometimes morethan one central leader may develop. This isknown as co-dominant leaders. Select the mostpromising (healthiest, best positioned) fromamong the multiple leaders and remove the oth-ers.

Pruning at planting simply to remove leafarea to “balance” roots and shoots is no longeran accepted practice. It reduces the plant’s pho-tosynthetic capacity which, in turn, reduces the“fuel” available to grow new roots. Only underthe most extreme conditions of hot summerplanting without irrigation should trees bepruned just to balance roots and shoots.

Large TreesProper pruning also helps to prevent injury

and damage to life and property. This usually in-volves the removal of large branches or limbsfrom trees. Where tree limbs are near power lines,call the power company and ask them to removethem. Do not try to remove tree limbs from powerlines yourself.

Low-hanging branches may cause injury to in-dividuals mowing the lawn or walking under thetree. Also, branches sometimes rub against thehouse and roof. To remove branches that are over3" in diameter, use the double cut method. If thedouble cut method is not used, the branch maytear and splinter the trunk. This removes a largeportion of the bark, causing a large wound whichcalluses with difficulty and may further result inpermanent damage to the tree (Figure 29).

To double cut, first make ascore cut on the underside of the limb (about onefoot from the tree trunk). Several inches furtherout, make the first through-cut on the upper partof the limb (Figure 30). When the branch fallsaway, there is no splintering or tearing of bark offthe main tree trunk. Then remove the stub with a

Figure 29. Failure to usethe double cut method canresult in trunk damage andbark stripping.

Figure 30. Double cut method for large limb re-moval.

to begin,score limb here

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second through-cut, taking care not to cut intothe enlarged base of the limb called the branchcollar. (See “Basic Procedures in Pruning”).

Old, Overgrown ShrubsAnother aspect of pruning is the renewal of

declining shrubs. In renewal pruning, plant stressis minimized and continued survival is promotedif you remove one-third of the oldest, maturestems per year for three years. These large, oldbranches are removed at the ground level, leav-ing the young vigorous branches. The basalshoots that develop should be headed back todifferent lengths and selected for vigor by thethinning process (Figure 31).

Lilac wood often is more than 3 years old be-fore it flowers. Therefore, large, overgrown lilacbushes can gradually be cut back over a periodof years, but do not remove all the old floweringwood until the new growth begins to flower.Then the bush will flower every year and willnot have any barren years.

If it is essential to immediately reduce thesize of a shrub, rejuvenation pruning is appropri-ate for some species (Table 9). Cut back the en-tire top of the plant to the ground line. Many newshoots will grow from the base, and they will re-quire thinning. As much as 3/4 of the newgrowth should be removed, depending on thespecies (Figure 32).

Figure 31. Renewal pruning is best accomplished as a gradual process to reduce stress on the shrub.

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Table 9. Landscape plants which may be rejuve-nation pruned (completely cut back to theground)._______________________________________________

Scientific name Common name_______________________________________________

Buddleia davidii butterflybushForsythia ForsythiaHibiscus syriacus Shrub-altheaHydrangea arborescens ‘Grandiflora’ Hills-of-snowHydrangea quercifolia Oakleaf hydrangeaKerria japonica Japanese KerriaLigustrum vulgare PrivetLonicera HoneysuckleSpiraea SpireaSyringa Lilac________________________________________________

Some plants frequently suffer winter dieback of all above-ground stems. These may besafely rejuvenation pruned to produce rapid newgrowth. These “die-back” plants are consideredto be usefully winter hardy. They can be used forlandscaping purposes similar to an herbaceousperennial, even though severe rejuvenation prun-ing often is necessary.

Hedges, Espaliers, and TopiaryPlants are occasionally sheared to unnatural

shapes. Hedges as barriers are most common.However, hedges are often improperly pruned,with the sides sloped inward so that the base ismore narrow than the top. This shades the lowerportion of the hedge, preventing dense leaf

growth. Thus, the plants become leggy, thehedge becomes straggly, and the screening func-tion is not achieved. In proper hedge shearing,the top is shaped more narrow than the base.This means that light can penetrate to the lowerportions of the plants, growth can be maintained,and a leafy appearance over the entire height ofthe hedge can be attained (Figure 33).

Two other types of pruning plants to unusualshapes are espalier and topiary. An attractiveplant requires both dedicated effort and constantattention. Not all landscape designs are appropri-ate for such plants, and in all cases, their useshould be limited to focal points due to theirhighly unusual appearance.

Espaliering is the practice of training a treeor shrub to grow flat. Almost any tree or shrubcan be trained flat by continually removinggrowing points that go in unwanted directions.Allow the rest of the growing points to developin their own way.

Before locating a plant next to your house forespaliering, place an iron or wooden support afew inches away from the wall. This prevents

Figure 32. Rejuvenation pruning involves cutting back the top of the plant to the ground. Thin thenew shoots as they begin to grow to prevent excessive crowding.

Figure 33. A properly pruned hedge with narrowtop (A) and an improperly pruned hedge withwide top (B).

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damage to the wall and allows for plant supportand easy plant removal at a future date (Figure34).

Topiary is a shearing technique occasionallydone on boxwood, juniper, pyracantha, yew, andprivet. Sometimes fanciful figures are created.More typically, pompom forms of stems withclumps of foliage are desired. Part the branches

Figure 34. Some examples of classical espalier forms.

to find a basic form. Remove limbs you don’twant. Wherever you want to form a foliar clump,leave some branches and shear them to the out-line you desire. Remove all twigs and leavesalong branches between clumps. Each seasonnew branches and leaves will tend to fill in thespaces between clumps. Topiary plants should beconsidered “high maintenance” landscape com-ponents.

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Review & Study Questions

1. Describe the characterisitics of bare root versus machine balled nursery stock.2. Compare balled and burlapped root systems with those of container grown stock.3. Is summer a good planting time? Why or why not? What about fall?4. What is usually the best backfill to use when tree planting? What might make you change from

using this material?5. What should be done with the burlap on a B&B tree at the time of planting?6. What should be done with the wire basket on a B&B tree at the time of planting?7. How should you handle a papier-mache pot (“plantable container”) at planting?8. What is meant by the bathtub effect? Under what soil conditions is it likely to occur?9. When is staking and guying desirable? What is the correct way to do it?10. What is a desirbale annual rate of nitrogen fertilizer for woody plants?11. When should fertilizer be applied to landscape plants?12. List the seven main reasons for pruning.13. What factors influence correct timing for pruning? Give some examples.14. What are the two basic pruning cuts? Define each.15. Describe what is meant by the branch “collar” and how it should be treated when limb removal is

done.16. What is a “candle” on a needle evergreen tree and how should pruning be practiced on such

candles?17. Where is a central leader found on a shade tree? What should you do if multiple central leaders

develop?18. What is the purpose of using the double-cut method of large limb removal?19. Describe and differentiate between renewal and rejuvenation pruning.20. What is the key to success in hedge pruning to produce a hedge which is a solid wall of foliage

all the way to the ground?

For Additional Reading

Hensley, David L. Professional Landscape Management. Champaign, IL: Stipes. 1994.Watson, G. W. and E. B. Himelick. Principles and Practice of Planting Trees and Shrubs. Interna-

tional Society of Arboriculture. 1997.Eyewitness Garden Handbook. Pruning & Training. 1999.Gilman, Edward F. An Illustrated Guide to Pruning. Thomson Delmar Learning. 2002.Giles, Floyd. Landscape Construction Procedures, Techniques and Design. Champaign, IL: Stipes.

1999.

Websites of Interesthttp://bluestem.hort.purdue.edu/plant/http://ohioline.osu.edu/hyg-fact/1000/1014.htmlhttp://ohioline.osu.edu/hyg-fact/1000/1002.html