idaho master gardener handbook chapter 4

CHAPTER 4 IDAHO MASTER GARDENER PROGRAM HANDBOOK 4 - 1

I. Sexual Propagation 2

A. Seed 2

B. Germination 2

C. Methods of Breaking Dormancy 4

D. Starting Seeds 5

E. Transplanting and Handling 8

II. Asexual Propagation 9

A. Cuttings 9

B. Layering 12

C. Division 14

D. Grafting 14

E. Budding 16

F. Plant Tissue Culture 17

Further Reading 17

MASTER GARDENERIDAHOUNIVERSITY OF IDAHO EXTENSION

Chapter 4PLANT PROPAGATION

4 - 2 PLANT PROPAGATION CHAPTER 4

I. Sexual PropagationSexual propagation involves the union of the pol-len (male) with the egg (female) to produce aseed. The seed is made up of three parts: the outerseed coat, which protects the seed; the endosperm(cotyledon), which is a food reserve; and the em-bryo, which is the young plant itself. When a seedis mature and put in a favorable environment, itwill germinate, or begin active growth. In the fol-lowing section, seed germination and transplant-ing of seeds will be discussed.

A.SeedTo obtain quality plants, start with goodquality seed from a reliable dealer. Selectvarieties to provide the size, color, and habitof growth desired. Choose varieties adaptedto your area that will reach maturity beforean early frost. Many new vegetable andflower varieties are hybrids, which cost alittle more than open pollinated types. How-ever, hybrid plants usually have more vigor,more uniformity, and better production thannonhybrids and sometimes have specificdisease resistance or other unique culturalcharacteristics. Disadvantages of hybrids:seed cannot be saved as they do not breedtrue, and they may have a higher fertilityrequirement.

Although some seeds will keep for severalyears if stored properly, it is advisable topurchase only enough seed for the currentyear’s use. Good seed will not contain seedof any other crop, weed seeds, or other de-bris. The seed packet usually indicates es-sential information about the variety, theyear for which the seeds were packaged,germination percentage you may typicallyexpect, and notes of any chemical seedtreatment. If seeds are obtained well in ad-vance of the actual sowing date or are storedsurplus seeds, keep them in a cool, dryplace. Do not freeze seed. Laminated foilpackets help ensure dry storage. Paper pack-ets are best kept in tightly-closed containersand maintained near 40°F in low humidity.Some gardeners save seed from their owngardens, however, such seed is the result ofrandom pollination by insects or other natu-ral agents and may or may not produceplants typical of the parents. Open pollinatedvarieties are best for seed saving. Vegetableseeds are discussed in Chapter 19.

B. GerminationFour environmental factors affect germina-tion: water, light, oxygen, and heat.1. Water—The first step in the germination

process is absorption of water. Eventhough seeds have great absorbing powerdue to the nature of the seed coat, theamount of available water in the germina-tion medium affects the uptake of water.An adequate, continuous supply of wateris important to ensure germination. Oncethe germination process begins, a dry pe-riod will cause the death of the embryo.

2. Light—Light is known to stimulate or toinhibit germination of some seed. TheBean seed with interior parts indicated

Embryo

Seed coat

Cotyledon

Chapter 4

Plant PropagationSusan M. Bell, Extension Educator, Ada County


light reaction involved hereis a complex process. Somecrops that have a requirementfor light to assist seed germi-nation are ageratum, begonia,browallia, impatiens, lettuce,and petunia. Conversely, cen-taurea, annual phlox, ver-bena, and vinca will germi-nate best in the dark (Table1). Many other plant seedsare not specific in their lightor dark requirements.Seed catalogs and seed pack-ets often list germination orcultural tips for individualvarieties. When sowing light-requiring seed, do as naturedoes and leave them on thesoil surface. If they are cov-ered at all, cover them lightlywith fine peat moss or finevermiculite. These two mate-rials, if not applied tooheavily, will permit somelight to reach the seed andwill not limit germination.When starting seed in thehome, supplemental light canbe provided by fluorescentfixtures suspended 6 to 12inches above the seeds for 16hours a day.

3. Oxygen—In all viable seed,respiration takes place. Therespiration in dormant seed islow, but some oxygen is re-quired. The respiration rateincreases during germination,therefore, the medium inwhich the seeds are placed should beloose and well aerated. If the oxygen sup-ply during germination is limited or re-duced, germination can be severely re-tarded or inhibited.

4. Heat—A favorable temperature is an-other important requirement of germina-tion (Table 1). It not only affects the ger-mination percentage but also the rate ofgermination. Some seeds will germinateover a wide range of temperature,

whereas others require a narrow range.Many seed have minimum, maximum,and optimum temperatures at which theygerminate. For example, tomato seed hasa minimum germination temperature of50°F and a maximum temperature of95°F, but an optimum germination tem-perature of about 80°F. Where germina-tion temperatures are listed, they are usu-ally the optimum temperatures unlessotherwise specified. Generally, 65° to

Table 1. Seed requirements.

Approximate Optimumtime to seed Approximate germination Germinationbefore last germination temperature in light (L)

Plant spring frost time (days) (°F) or dark (D)

Begonia 12 weeks 10 to 15 70 LBrowallia or more 15 to 20 70 LGeranium 10 to 20 70 DLarkspur 5 to 10 55 DPansy (Viola) 5 to 10 65 DVinca 10 to 15 70 D

Dianthus 10 weeks 5 to 10 70 —Impatiens 15 to 20 70 LPetunia 5 to 10 70 LPortulaca 5 to 10 70 DSnapdragon 5 to 10 65 LStock 10 to 15 70 —Verbena 15 to 20 65 D

Ageratum 8 weeks 5 to 10 70 LAlyssum 5 to 10 70 —Broccoli 5 to 10 70 —Cabbage 5 to 10 70 —Cauliflower 5 to 10 70 —Celosia 5 to 10 70 —Coleus 5 to 10 65 LDahlia 5 to 10 70 —Eggplant 5 to 10 70 —Head lettuce 5 to 10 70 LNicotiana 10 to 15 70 LPepper 5 to 10 80 —Phlox 5 to 10 65 D

Aster 6 weeks 5 to 10 70 —Balsam 5 to 10 70 —Centaurea 5 to 10 65 DMarigold 5 to 10 70 —Tomato 5 to 10 80 —Zinnia 5 to 10 70 —

Cucumber 4 weeks 5 to 10 85 —Cosmos or less 5 to 10 70 —Muskmelon 5 to 10 85 —Squash 5 to 10 85 —Watermelon 5 to 10 85 —

( — ) means no specific light or dark requirements.


75°F is best for most plants. This oftenmeans the germination flats may have tobe placed on radiators, heating cables, orheating mats to maintain optimum tem-perature. The importance of maintainingproper soil temperature to achieve maxi-mum germination percentages cannot beover-emphasized.Germination will begin when certain in-ternal requirements have been met. Aseed must have a mature embryo, containa large enough endosperm to sustain theembryo during germination, and containsufficient hormones or auxins to initiatethe process.

C. Methods of Breaking DormancyOne of the functions of dormancy is to pre-vent a seed from germinating before it issurrounded by a favorable environment. Insome trees and shrubs, seed dormancy isdifficult to break, even when the environ-ment is ideal. Various treatments are per-formed on the seed to break dormancy andbegin germination.1. Seed scarification—Seed scarification

involves breaking, scratching, or soften-ing the seed coat so that water can enterand begin the germination process. Thereare several methods of scarifying seeds.a. In acid scarification, seeds are put in a

glass container and covered with con-centrated sulfuric acid. The seeds aregently stirred and allowed to soakfrom 10 minutes to several hours, de-pending on the hardness of the seedcoat. When the seed coat has becomethin, the seeds can be removed,washed, and planted.

b. Another scarification method is me-chanical. You may file seeds with ametal file, rub them with sandpaper, orcrack them with a hammer to weakenthe seed coat.

c. Hot water scarification involves put-ting the seed into hot water (170° to212°F). The seeds are allowed to soakin the water, as it cools, for 12 to 24hours and then planted.

d. You also may try warm, moist scarifi-cation. In this case, seeds are stored in

nonsterile, warm, damp containerswhere the seed coat will be brokendown by decay over several months.

2. Seed stratification—Seeds of some fall-ripening trees and shrubs of the temperatezone will not germinate unless chilledunderground as they overwinter. This so-called “after-ripening” may be accom-plished artificially by a practice calledstratification.a. The following procedure is usually

successful. Put sand or vermiculite in aclay pot to about 1 inch from the top.Place the seeds on top of the mediumand cover with 1/2-inch of sand or ver-miculite. Wet the medium thoroughlyand allow excess water to drainthrough the hole in the pot. Place thepot containing the moist medium andseeds in a plastic bag and seal. Placethe bag in a refrigerator (not freezer).Periodically check to see that the me-dium is moist, but not wet. Additionalwater will probably not be necessary.After 10 to 12 weeks, remove the bagand pot from the refrigerator. Removethe bag and set the pot in a warm placein the house. Water often enough tokeep the medium moist. Soon theseedlings should emerge. When theyoung plants are about 2 inches tall,transplant them into pots to grow untilit is time to set them outside.

b. Another procedure for starting seedsuses sphagnum moss or peat moss.Wet the moss thoroughly, thensqueeze out the excess water with yourhands. Mix seed with the sphagnum orpeat and place in a plastic bag. Seal thebag and put it in a refrigerator. Checkperiodically. If there is condensationon the inside of the bag, the processwill be successful. After 10 to 12weeks, remove the bag from the refrig-erator. Plant the seeds in pots to germi-nate and grow. Handle seeds carefully.Often the small roots and shoots areemerging at the end of the stratifica-tion period. Care must be taken not tobreak these off.


c. Temperatures in the range of 35° to45°F are effective for stratification.Most refrigerators operate in thisrange. Seeds of most fruit and nut treescan be successfully germinated bythese procedures. Seeds of peachesshould be removed from the hard pit.Care must be taken when cracking thepits. Any injury to the seed itself canbe an entry path for disease organisms.

D.Starting Seeds1. Media—A wide range of materials can be

used to start seeds, from plain vermiculiteor mixtures of soilless media to the vari-ous amended soil mixes. With experi-ence, you will learn to determine whatworks best under your conditions. How-ever, keep in mind what makes a goodgerminating medium. It should be ratherfine and uniform, yet well-aerated andloose. It should be free of insects, diseaseorganisms, and weed seeds. It should alsobe of low fertility or total soluble saltsand capable of holding and moving mois-ture by capillary action. One mixture thatsupplies these factors is a combination of1/3 sterilized soil, 1/3 sand or vermiculiteor perlite, and 1/3 peat moss. Do not usegarden soil by itself to start seedlings; itis not sterile, it is often too heavy, and itwill not drain well.a. The importance of using a sterile me-

dium and container cannot be over-emphasized. The home gardener cantreat a small quantity of soil in anoven. Place the slightly moist soil in aheat-resistant container in an oven setat about 250°F. Use a candy or meatthermometer to ensure that the mixreaches a temperature of 180°F for 30minutes. Avoid over-heating as thiscan be extremely damaging to the soil.Be aware that the soil will release veryunpleasant odors in the process of ster-ilization. This treatment should pre-vent damping-off and other plant dis-eases, as well as eliminate potentialplant pests.

b. An artificial, soilless mix also providesthe desired qualities of a good germi-nation medium. The basic ingredients

of such a mix are sphagnum peat mossand vermiculite, both of which aregenerally free of diseases, weed seeds,and insects. The ingredients are alsoreadily available, easy to handle, light-weight, and produce uniform plantgrowth. “Peat-lite” mixes or similarproducts are commercially available orcan be made at home using this recipe:4 quarts of shredded sphagnum peatmoss, 4 quarts of fine vermiculite, 1tablespoon of superphosphate, and 2tablespoons of ground limestone. Mixthoroughly. These mixes have littlefertility, so seedlings must be wateredwith a diluted fertilizer solution soonafter they emerge.

2. Containers—Flats and trays can be pur-chased or you can make your own fromscrap lumber. A convenient size tohandle would be about 12 to 18 incheslong and 12 inches wide with a depth ofabout 2 inches. Leave cracks of about1/8-inch between the boards in the bot-tom or drill a series of holes to ensuregood drainage.a. You can also make your own contain-

ers for starting seeds by recycling suchthings as cottage cheese containers, thebottoms of milk cartons, or bleachcontainers and pie pans, as long asgood drainage is provided. Washgrowing containers and implements toremove any debris, then rinse in a so-lution of one part chlorine bleach tonine parts water. At least one companyhas developed a form for shapingnewspaper into pots, and another hasdeveloped a method for the consumerto make and use compressed blocks ofsoil mix instead of pots.

b. Clay or plastic pots can be used andnumerous types of pots made of com-pressed peat are also on the market.Plant bands and plastic cell packs arealso available. Each cell or minipotholds a single plant that reduces therisk of root injury when transplanting.Peat pellets, peat or fiber-based blocks,and expanded foam cubes can also beused for sowing.


3. Seeding—The proper time for sowingseeds for transplants depends upon whenplants may safely be moved out-of-doorsin your area. This period may range from4 to 12 weeks before transplanting, de-pending upon the speed of germination,the rate of growth, and the cultural condi-tions provided. A common mistake is tosow the seeds too early and then attemptto hold the seedlings back under poorlight or improper temperature ranges.This usually results in tall, weak, spindlyplants that do not perform well in the gar-den.a. After selecting a container, fill it to

within 3/4-inch of the top with moist-ened growing medium. For very smallseeds, at least the top 1/4-inch shouldbe a fine, screened mix or a layer ofvermiculite. Firm the medium at thecorners and edges with your fingers ora block of wood to provide a uniform,flat surface.

b. For medium and large seeds, make fur-rows 1 to 2 inches apart and 1/8- to1/4-inch deep across the surface of thecontainer using a narrow board or potlabel. By sowing in rows, good lightand air movement results, and if damp-ing-off fungus does appear, there isless chance of it spreading. Seedlingsin rows are easier to label and handleat transplanting time than those thathave been sown in a broadcast manner.Sow the seeds thinly and uniformly inthe rows by gently tapping the packetof seed as it is moved along the row.Lightly cover the seed with dry ver-miculite or sifted medium if they re-quire darkness for germination. A suit-able planting depth is usually abouttwo to three times the diameter of theseed.

c. Do not plant seeds too deeply. Ex-tremely fine seeds such as petunia, be-gonia, and snapdragon are not covered,but lightly pressed into the medium orwatered in with a fine mist. If theseseeds are broadcast, strive for a uni-form stand by sowing half the seeds in

one direction, then sowing the remain-ing seed the other direction to form acrossed pattern.

d. Large seeds are frequently sown into asmall container or cell pack that elimi-nates the need for early transplanting.Usually two or three seeds are sownper unit and later thinned to allow thestrongest seedling to grow.

4. Seed tape—Most garden stores and seedcatalogs offer indoor and outdoor seedtapes. Seed tape has precisely spacedseeds enclosed in an organic, water-soluble material. When planted, the tapedissolves and the seeds germinate nor-mally. Seed tapes are especially conve-nient for tiny, hard-to-handle seeds.However, tapes are much more expensiveper seed. Seed tapes allow uniform emer-gence, eliminate overcrowding, and per-mit sowing in perfectly straight rows.The tapes can be cut at any point for mul-tiple-row plantings, and thinning is rarelynecessary.a. A homemade “seed tape” can be fash-

ioned from 2-ply toilet paper and pastemade with flour and water. Separatethe two paper layers, then use a tooth-pick with a dab of flour paste on it topick up and place seeds on one of thepaper layers. Once all seeds areplaced, put the two layers back to-gether while the paste is still wet androll the “tape” up for later use. The toi-let paper, once covered with soil, willrapidly decay leaving no trace.

5. Pregermination—Another method ofstarting seeds is pregermination. Thismethod involves sprouting the seeds be-fore they are planted in pots or in the gar-den. This reduces the time to germina-tion, as the temperature and moisture areeasy to control. A high percentage of ger-mination is achieved since environmentalfactors are optimum.a. Lay seeds between two paper towels

or on a layer of vermiculite in a shal-low pan. Keep them moist and in awarm place. When roots begin toshow, place the seeds in containers or


plant them directly into the garden.While transplanting seedlings, be care-ful not to break off tender roots. Con-tinued attention to watering is critical.

b. When planting seeds in a containerthat will be set out in the garden later,place one seed in a 2- to 3-inch con-tainer. Plant the seeds at only one-halfthe recommended depth. Gently pressa little soil over the sprouted seed andthen add about 1/4-inch of milledsphagnum peat or sand to the soil sur-face. These materials will keep the sur-face uniformly moist and are easy forthe shoot to push through. Keep theseedlings in a warm place and care forthem as for any other newly trans-planted seedlings.

c. A convenient way to plant small, deli-cate, pregerminated seeds is to sus-pend them in a gel. You can make agel by blending cornstarch with boil-ing water to a consistency that is thickenough so the seeds will stay sus-pended. Be sure to cool thoroughly be-fore adding seeds. Place the gel withseedlings in a plastic bag with a holein it. Squeeze the gel through the holealong a premarked garden row. Spac-ing of seeds is determined by the num-ber of seeds in the gel. If the spacing istoo dense, add more gel; if too wide,add more seeds. The gel will keep thegerminating seeds moist until they es-tablish themselves in the garden soil.

5. Watering—After the seed has been sown,moisten the planting mix thoroughly. Usea fine mist or place the containers in apan or tray that contains about 1 inch ofwarm water. Avoid splashing or exces-sive flooding, which might displace smallseeds. When the planting mix is satu-rated, set the container aside to drain. Thesoil should be moist but not wet.a. Ideally, seed flats should remain suffi-

ciently moist during the germinationperiod without having to add water.One way to maintain moisture is toslip the whole flat or pot into a clearplastic bag after the initial watering.

The plastic should be at least 1 inchfrom the soil. Placing a popsicle stickor pencil in the middle of the flat willhold the plastic off the soil and plants.Keep the container out of direct sun-light, otherwise the temperature mayrise to the point where the seeds willbe harmed. Many home gardenerscover their flats with panes of glassinstead of using a plastic bag. Be sureto remove the plastic or glass cover assoon as the first seedlings appear. Sur-face watering can then be practiced.

b. Lack of uniformity, overwatering, ordrying out are problems related tomanual watering. Excellent germina-tion and moisture uniformity can beobtained with a low-pressure mistingsystem or subirrigation (watering frombelow). Flats or pots must not sit inwater constantly as the soil may ab-sorb too much water, and the seedswill rot due to lack of oxygen.

6. Temperature and light—Several factorsfor good germination have already beenmentioned. The last item, and by nomeans the least important, is temperature.Since most seeds will germinate best atan optimum temperature that is usuallyhigher than most home night tempera-tures, special warm areas must be pro-vided. The use of thermostatically con-trolled heating cables is an excellentmethod of providing constant heat (seeGermination section on page 3-2).a. After germination and seedling estab-

lishment, move the flats to a light,airy, cooler location, at a 55° to 60°Fnight temperature and a 65° to 70°Fday reading. This will prevent soft,leggy growth and minimize disease.Some crops, of course, may germinateor grow best at a different constanttemperature and must be handled sepa-rately from the rest of the plants. Readas much as you can about the plantsyou are trying to grow.

b. Seedlings must receive bright light af-ter germination. Place them in a win-dow facing south, if possible. If a


large, bright window is not available,place the seedlings under a fluorescentlight. Use two 40-watt, cool-whitefluorescent tubes or special plantgrowth lamps. Position the plants 6 to8 inches from the tubes and keep thelights on for 14 to 16 hours each day.As the seedlings grow, the lightsshould be raised.

E. Transplanting and HandlingIf the plants have not been seeded in indi-vidual containers, they must be transplatedto give them proper growing space. One ofthe most common mistakes made is leavingthe seedlings in the seed flat too long. Theideal time to transplant young seedlings iswhen they are small as there is less dangerfrom transplant shock. This is usually aboutthe time the first true leaves appear above orbetween the cotyledons (the cotyledonssometimes called “seed leaves” are not trueleaves). Avoid letting plants get hard,stunted, or tall and leggy.1. Seedling growing mixes and containers

can be purchased or prepared similar tothose mentioned for germinating seed.The medium should contain more plantnutrients than a germination mix. Somecommercial soilless mixes have fertilizeralready added. When fertilizing, use asoluble houseplant fertilizer at the raterecommended by the manufacturer, aboutevery 2 to 3 weeks after the seedlings areestablished. Remember that young seed-lings can easily be damaged by too muchfertilizer, especially if they are undermoisture stress.

2. To transplant, carefully dig up the smallplants with a knife or wooden plant label.Let the group of seedlings fall apart andpick out individual plants. Gently easethem apart in small groups that will makeit easier to separate individual plants.Avoid tearing roots in the process.Handle small seedlings by their leaves,not by their delicate stems. Punch a holein the medium into which the seedlingwill be planted. Make it deep enough sothat the seedling can be put at the samedepth it was growing at in the seed flat.

After planting, firm the soil and watergently. Keep newly transplanted seed-lings in the shade for a few days, or placethem under fluorescent lights. Keep themaway from direct heat sources. Continuewatering and fertilizing as in the seedflats.

3. Most plants transplant well and can bestarted indoors, but a few plants are diffi-cult to transplant. These are generally di-rectly seeded outdoors or sown directlyinto individual containers indoors. Ex-amples include zinnias and cucurbits,such as melons and squash.

4. Containers for transplanting—There is awide variety of containers from which tochoose for transplanting seedlings. Thesecontainers should be economical, du-rable, and make good use of space. Thetype selected will depend on the type ofplant to be transplanted and individualgrowing conditions. Small plastic potsmay be used, but they waste a great dealof space and may not dry out rapidlyenough for the seedling to have sufficientoxygen for proper development.a. Many types of containers are available

commercially. Those made out ofpressed peat can be purchased in vary-ing sizes. Individual pots are inexpen-sive and can be planted directly intothe garden. When setting out plantsgrown in peat pots, be sure to coverthe pot completely. If the top edge ofthe peat pot extends above the soillevel, it may act as a wick and drawwater away from the soil and roots. Toavoid this, tear off the top lip of thepot and then plant.

b. Compressed peat pellets, when soakedin water, expand to form compact, in-dividual pots. They waste no space,don’t fall apart as badly as peat pots,and can be set directly out in the gar-den.

c. In addition, many homeowners find avariety of materials from around thehouse to use for containers. Thesehomemade containers should be deepenough to provide adequate soil and


have plenty of drainage holes in thebottom.

5. Hardening plants—Hardening off is theprocess of altering the quality of plantgrowth to withstand the change in envi-ronmental conditions that occurs whenplants are transferred from a greenhouseto the garden. Severe sunscald or a stop-page in growth may occur if plants pro-duced in the home are planted outdoorswithout a transition period. Hardening offis most critical with early crops, whenadverse climatic conditions can be ex-pected.a. Hardening off can be accomplished by

gradually lowering temperature andrelative humidity and reducing water.This procedure results in an accumula-tion of carbohydrates and a thickeningof cell walls. A change from a soft,succulent type of growth to a firmer,harder type occurs.

b. This process should be started at least2 weeks before planting in the garden.If possible, plants should be moved toa 45° to 50°F temperature either in-doors or outdoors in a shady location.A coldframe is excellent for this pur-pose. When put outdoors, plantsshould be shaded, then graduallymoved into sunlight. Start with a 15-to 20-minute exposure. Each daygradually increase the length of expo-sure time to outside temperatures.Don’t put tender seedlings outdoors onwindy days or when temperatures arebelow 45°F.

c. Reduce the frequency of watering toslow their growth, but don’t allowplants to wilt. Even cold-hardy plantswill be hurt if exposed to freezing tem-peratures before they are hardened.After proper hardening, however, theycan be planted outdoors and lightfrosts will not damage them.

d. The hardening off process is intendedto slow plant growth. If carried to theextreme of actually stopping plantgrowth, significant damage can bedone to certain crops. For example,

cucumbers and melons will stop allgrowth, while cauliflower will makethumb-size heads and fail to developfurther if hardened too severely.

II. Asexual PropagationAsexual propagation is the best way to maintainsome species, particularly an individual that bestrepresents that species. Clones are groups ofplants that are identical to their parent or motherplant. The Bartlett pear (1770) and the Deliciousapple (1870) are two examples of clones thathave been asexually propagated for many years.The major methods of asexual propagation arecuttings, layering, division, and budding/grafting.Cuttings involve rooting a severed piece of theparent plant; layering involves rooting a part ofthe parent plant and then severing it later; andbudding and grafting is joining two plant partsfrom different varieties.

A.CuttingsMany types of plants, both woody and her-baceous, are frequently propagated by cut-tings. A cutting is a vegetative plant partthat is severed from the parent plant in orderto regenerate itself, thereby forming a wholenew plant.1. Take cuttings with a sharp blade to re-

duce injury to the parent plant. Beforeusing the knife to cut, dip the cutting toolinto rubbing alcohol and allow it to dry oruse a mixture of one part bleach to nineparts water to disinfect the blade and toprevent transmitting diseases. Removeflowers and flower buds from cuttings toallow the cutting to use its energy andstored carbohydrates for root and shootformation rather than fruit and seed pro-duction.a. To hasten rooting, increase the number

of roots, or to obtain uniform rooting(except on soft, fleshy stems), use arooting hormone, preferably one con-taining a fungicide. Prevent possiblecontamination of the entire supply ofrooting hormone by putting a smallamount in a separate container for im-mediate use. Do not dip cuttings di-rectly into the original container.


Table 2. Selected herbaceous plants that can be propagated from cuttings.

ApproximatePlant Type of time to root

Common name Scientific name cutting (weeks)*

African violet Saintpaulia spp. leaf 3 to 4Aluminum plant Pilea spp. stem 2 to 3

Aloe Aloe spp. leaf 4 to 6Aphelandra Aphelandra sp. stem 2 to 3Arrowhead plant Syngonium podophyllum stem 2 to 3Begonia Begonia spp. stem 2

(fibrous rooted)whole leaf or 4 to 5leaf section (Rex)

Cactus Cephalocereus senilis stem 3 to 4Opuntia microdasys stem 3 to 4

Chrysanthemum Chrysanthemum spp. stem 1 to 2Carnation Dianthus spp. stem 2 to 3Coleus Coleus blumei stem 1 to 2

Crown of thorns Euphorbia splendens stem 4 to 5Dahlia Dahlia spp. stem or 3 to 4

leaf-budDieffenbachia Dieffenbachia spp. stem 4 to 6

(dumbcane)Dracaena Dracaena spp. stem 3 to 4Echeveria Echeveria spp. stem or leaf 4 to 6

Euphorbia Euphorbia spp. stem 4 to 6Fittonia Fittonia spp. stem 2 to 3Fuchsia Fuchsia spp. (also hybrids) stem 1 to 2

Geranium Pelargonium spp. stem 1 to 2Hoya Hoya spp. stem 3 to 4Hydrangea Hydrangea spp. stem 2 to 3

Impatiens Impatiens spp. stem 2 to 3

b. If hormone powder is used, only avery light coating is necessary. Tap offany excess onto a sheet of paper.

2. Insert cuttings into a rooting mediumsuch as coarse sand, vermiculite, steril-ized soil, water, or a mixture of peat andperlite. A pencil can be used to make ahole in the medium for easier insertionand to prevent the removal of hormonepowder from the cut surface.a. It is important to choose the correct

rooting medium to get optimum root-ing in the shortest time. In general, therooting medium should be sterile, lowin fertility, drain well enough to pro-vide oxygen, and retain enough mois-ture to prevent water stress. Moistenthe medium before inserting cuttings,and keep it evenlymoist while cut-tings are rootingand forming newshoots. Place stemand leaf cuttings inindirect light. Rootcuttings can bekept in the darkuntil new shootsappear.

3. Stem cuttings—Nu-merous plant speciesare propagated bystem cuttings (Table2). Some can be takenat any time of theyear, but stem cut-tings of many woodyplants must be takenduring the fall or inthe dormant season.Tip, medial, cane,single and doubleeye, and heel are allexamples of stem cut-tings.a. Tip cuttings: De-

tach a 2- to 4-inchpiece of stem withtwo or three nodes,including the ter-

minal bud. Make the bottom cut 1/4-inch below a node. Remove lowerleaves from the cutting that would bein contact with the medium. Dip thestem in rooting hormone if desired.Gently tap the end of the cutting to re-move excess hormone. Insert the cut-ting deeply enough into the media tosupport itself (about half way). At leastone node must be below the surface.

b. Medial cuttings: Make the first cut justabove a node, and the second cut justbelow another node 2 to 4 inches down

Tip cutting Medial cuttings


Table 2. (cont’d)

ApproximatePlant Type of time to root

Common name Scientific name cutting (weeks)*

Ivy several genera and species stem 2 to 3Jade Crassula spp. stem or leaf 4 to 5

Kalanchoe Kalanchoe spp. stem or leaf 4 to 5(bryophyllum)

Lantana Lantana sp. stem 3 to 4

Monstera Monstera deliciosa stem 4 to 5(Swiss cheeseplant)

Mint Mentha spp. stem 2 to 3

Peperomia Peperomia sp. leaf, leaf-bud 4 to 6or stem

P. obtusifolia leaf-bud or stem 4 to 6P. obtusifolia variegata leaf-bud or stem 4 to 6

Periwinkle (myrtle) Vinca spp. stem 3 to 4

Petunia Petunia hybrids stem 2 to 3Philodendron Philodendron spp. stem 2 to 4Piggyback plant Tolmiea menziesii leaf with 3 to 4

plantletPothos Scindapsus aureus stem 2 to 3

Poinsettia Euphorbia pulcherrima stem 2 to 3Sansevieria Sansevieria spp. leaf, leaf 4 to 6

(snake plant) sectionVelvet plant Gynura spp. stem 1 to 2Wandering jew Tradescantia spp. stem 2 to 3

Zebrina spp.

*The indicated time for rooting is only approximate and may be longer under someconditions. Where new shoots must develop in addition to roots, the time requiredfor shoot development is often longer.

Source: Propagating Herbaceous Plants from Cuttings, PNW 151.

Cane cuttings

the stem. The terminal bud is not nec-essary for this kind of stem cutting.Prepare and insert the cutting as youwould a tip cutting. Be sure to positionright side up. Axial buds are alwaysabove leaves.

c. Cane cuttings: Cut cane-like stems intosections containing one or two “eyes”or nodes. Dust ends with fungicide oractivated charcoal. Allow to dry sev-eral hours. Lay horizontally with abouthalf of the cutting below the mediasurface, eye facing upward. Cane cut-tings are usually potted when roots andnew shoots appear. This method isused with dumbcane (Dieffenbachia).

d. Single eye cuttings: The eye refers tothe node. This is used for plants with

alternate leaves when space orstock material are limited. Cutthe stem about 1/2 inch aboveand 1/2 inch below a node. Placecutting horizontally or verticallyin the medium.

e. Double eye cuttings: Thisis used for plants with op-posite leaves when spaceor stock material is lim-ited. Cut the stem about1/2 inch above and 1/2inch below the same node.Insert the cutting verticallyin the medium with thenode just touching the sur-face.

f. Heel cuttings: This methoduses plant material withwoody stems. Make ashield-shaped cut abouthalfway through the woodaround a leaf and axialbud. Insert the shield hori-zontally into the medium.

4. Leaf cuttings—Leaf cuttingsare used almost exclusivelyfor a few indoor houseplants.Leaves of most other plantswill either produce a fewroots but no plant, or theyjust decay. Covering leaf cut-

Heel cuttings

Single eye (left) and double eye (right) cuttings


tings with a plastic bag willmaintain moisture in the me-dium and humidity aroundthe cutting.

a. Whole leaf with petiole: Detach theleaf and up to 1 1/2 inches of petiole.Insert the lower end of the petiole intothe medium. One or more new plantswill form at the base of the petiole.The leaf may be severed from the newplants when they have their own roots,and the petiole reused. This method isused for African violets.

main vein. Lay leaves flat on the me-dium. A new plant will arise at thevein.Cut snake plant leaves into 2-inch sec-tions. Consistently make the lower cutslanted and the upper cut straight soyou can tell which is the top. Insert thecuttings vertically into the medium.Eventually a new plant will appear atthe base of the cutting. These andother succulent cuttings will rot if kepttoo moist. No plastic bag is neededaround succulents.

5. Root cuttings—Root cuttings are usuallytaken from 2- to 3-year-old plants duringtheir dormant season when they have alarge carbohydrate supply. Root cuttingsof some species produce new shoots,which then form their own root systems,while root cuttings of other plants de-velop root systems before producing newshoots.a. Plants with large roots: Make a

straight top cut and a slanted cut 2 to 6inches below the first cut. This willhelp you determine what portion is thetop. Store about 3 weeks in moist saw-dust, peat moss, or sand at 40°F. Re-move from storage. Insert the cuttingvertically with the top approximatelylevel with the surface of the rootingmedium. This method is often usedoutdoors.

Split vein Leaf section

b. Whole leaf without petiole: This isused for plants with sessile leaves. In-sert the cutting vertically into the me-dium. A new plant will form from theaxillary buds. The leaf may be re-moved when the new plant has its ownroots. This method is used with jadeplants.

c. Split vein: Detach a leaf from the stockplant. Slit its veins on the lower leafsurface. Lay and pin the cutting, lowerside down, on the medium. New plantswill form at each cut. If the leaf tendsto curl up, hold it in place by coveringthe margins with the rooting medium.This method is used with Rex bego-nias. A plastic bag around the con-tainer and leaf will help keep the leaffrom drying out.

d. Leaf sections: This method is fre-quently used with snake plant (Sanse-vieria) and Rex begonias. Cut begonialeaves into wedges with at least one

Whole leaf with petiole Whole leaf without petiole

Plants with small roots

Plants with large roots

b. Plants with small roots: Take a 2- to3-inch section of root. Insert the cut-ting horizontally about 1/2 inch belowthe medium surface. This method isusually used indoors or in a hotbed.

B. LayeringStems still attached to their parent plantsmay form roots where they touch a rooting


medium. Severed from the parent plantlater, the rooted stem becomes a new plant.This method of vegetative propagation,called layering, promotes a high success ratebecause it prevents water stress and the lossof carbohydrate shortage that plagues cut-tings.Some plants layer themselves naturally, butsometimes plant propagators assist the pro-cess. Layering is enhanced by woundingone side of the stem or by bending it verysharply.1. Tip layering—Dig a hole 3 to 4 inches

deep. Insert the shoot tip and cover itwith soil. The tip grows downward first,then bends sharply and grows upward.Roots form at the bend, and the recurvedtip becomes a new plant. Remove the tiplayer from the mother plant and plant it inearly spring or fall. Examples: purple andblack raspberries and trailing blackberries.

5. Air layering—Air layering is used topropagate some indoor plants with thickstems, or to rejuvenate them when theybecome leggy. Make an upward slantingcut one half way through the stem justbelow a node. Hold the slit open with atoothpick laid sideways or a bit of sphag-num moss. Surround the wound with wet,unmilled sphagnum moss. Wrap plasticor foil around the sphagnum moss and tieit in place above and below the wound.When roots pervade the moss, cut theplant off below the root ball. Examples:dumbcane and rubber tree.

Note: The following propagation methods can allbe considered types of layering, as the newplants form before they are detached fromtheir parent plants.

6. Stolons and runners—A stolon is a hori-zontal, often fleshy stem that can root andproduce new shoots where it touches themedium. A runner is a slender stem thatoriginates in a leaf axil and grows alongthe ground or downward from a hangingbasket, producing a new plant at its tip.Plants that produce stolons or runners are

Tip layering Simple layering

2. Simple layering—Bend the stem to theground. Cover part of it with soil, leavingthe last 6 to 12 inches exposed. Bend thetip into a vertical position and stake it inplace. The sharp bend will often inducerooting, but wounding the lower side ofthe branch may help. Examples: rhodo-dendron and honeysuckle.

3. Compound layering—This method worksfor plants with flexible stems. Bend thestem to the rooting medium as for simplelayering, but alternately cover and exposestem sections. Wound the lower side ofstem sections to be covered. Examples:heart-leaf philodendron and pothos.

4. Mound (stool) layering—Cut the plantback to 1 inch above the ground duringthe dormant season. Mound soil over theemerging shoots in the spring to enhancetheir rooting. Examples: gooseberries andapple rootstocks.

Compound layering

Mound layering Air layering

Stolons and runners

Offsets


propagated by severing the new plantsfrom their parent stems. Plantlets at thetips of runners may be rooted while stillattached to the parent, or detached andplaced in a rooting medium. Examples:strawberry and spider plant.

7. Offsets—Plants with a rosetted stem of-ten reproduce by forming new shoots attheir base or in leaf axils. Sever the newshoots from the parent plant after theyhave developed their own root system.Unrooted offsets of some species may beremoved and placed in a rooting medium.Some of these must be cut off, while oth-ers may simply be lifted off of the parentstem. Examples: date palm, haworthia,bromeliads, and many cacti.

8. Separation—Separation is a term appliedto a form of propagation by which plantsthat produce bulbs or corms multiply.a. Bulbs: New bulbs form beside the

originally planted bulb. Separate thesebulb clumps every 3 to 5 years forlargest blooms and to increase bulbnumber. Dig up the clump after theleaves have withered. Gently pull thebulbs apart and replace them immedi-ately so that their roots can begin todevelop. Small, new bulbs may notflower for 2 or 3 years, but large onesshould bloom the first year. Examples:tulip and narcissus.

with a fungicide and store in a coolplace until planting time. Examples:crocus and gladiolus.

b. Corms: A large new corm forms ontop of the old corm, and tiny cormelsform around the large corm. After theleaves wither, dig up the corms andallow them to dry in indirect light for2 or 3 weeks. Remove the cormels,then gently separate the new cormfrom the old corm. Dust all new corms

Division

Separation corms

C. DivisionPlants with more than one rooted crownmay be divided and the crowns plantedseparately. If the stems are not jointed, gen-tly pull the plants apart. If the crowns areunited by horizontal stems, cut the stemsand roots with a sharp knife to minimize in-jury. Divisions of some outdoor plantsshould be dusted with a fungicide beforethey are replanted. Examples: snake plant,iris, prayer plant, and day lilies.1. Most perennials left in the same place for

more than 3 years are likely to be over-grown, overcrowded, have dead or un-sightly centers, and in need of basic feed-ing and soil amendment. The center ofthe clump will grow poorly, if at all, andthe flowers will be sparse. The clumpwill deplete the fertility of the soil as theplant crowds itself.a. To divide mature clumps of perenni-

als, select only vigorous side shootsfrom the outer part of the clump. Dis-card the center of the clump. Dividethe plant into sections of three to fiveshoots each. Be careful not to over-divide; too small a section will notgive much color the first year after re-planting.

b. Divide perennials when the plants aredormant, just before a new season ofgrowth, or in the fall so they can be-come established before the groundfreezes.

D.GraftingGrafting and budding are methods ofasexual plant propagation that join plantparts so they will grow as one plant. These


techniques are used to propagate cultivarsthat will not root well as cuttings or whoseown root systems are inadequate. One ormore new cultivars can be added to existingfruit and nut trees by grafting or budding.1. The portion of the cultivar that is to be

propagated is called the scion. It consistsof a piece of shoot with dormant budsthat will produce the stem and branches.The rootstock, or stock, provides the newplant’s root system and sometimes thelower part of the stem. The cambium is alayer of cells located between the woodand bark of a stem from which new barkand wood cells originate.

2. Four conditions must be met for graftingto be successful: (1) The scion and root-stock must be compatible, (2) each mustbe at the proper physiological stage, (3)the cambial layers of the scion and stockmust meet, and (4) the graft union mustbe kept moist until the wound has healed.a. Cleft grafting: Cleft grafting is often

used to change the cultivar or topgrowth of a shoot or a young tree (usu-ally a seedling). It is especially suc-cessful if done in the early spring.Collect scion wood 3/8- to 5/8-inch indiameter. Cut the limb or small treetrunk off at the area that it is to be re-

Cleft graft (correct method ontop; incorrect method below)

used on large limbs, although these areoften infected before the wound cancompletely heal. Collect scion wood3/8- to 1/2-inch in diameter when theplant is dormant, and store the woodwrapped in moist paper in a plastic bagin the refrigerator. Saw off the limb ortrunk of the rootstock to be worked. Inthe spring, when the bark easily sepa-rates from the wood, make a 1- to 2-inch diagonal cut on one side of thescion, and a 1 1/2-inch diagonal cut onthe other side. Leave two buds abovethe longer cut. Slice through the barkof the stock cutting a little wider thanthe scion. Insert the scion between thebark and wood with the longer cutagainst the wood. Nail the graft inplace with flat-headed wire nails.Cover all wounds with grafting wax.

c. Whip or tongue grafting: This methodis often used for material 1/4- to 1/2-

worked. Make a 2-inch vertical cutthrough the center of the limb or trunk.Be careful not to tear the bark. Keepthis cut wedged apart. Cut the lowerend of each scion piece into a wedge.Prepare two scion pieces 3 to 4 incheslong. Insert the scions at the outeredges of the cut in the stock. Tilt thetop of the scion slightly outward andthe bottom slightly inward to be surethe cambial layers of the scion andstock touch. Remove the wedge prop-ping the slit open and cover all cut sur-faces with grafting wax.

b. Veneer or bark grafting. Unlike mostgrafting methods, bark grafting can be

Bark graft

Cleft graft with both scionsinserted at slight angles. All cutsurfaces should be waxed over.


inch in diameter. The scion and root-stock are usually of the same diameter,but the scion may be narrower than thestock. This strong graft heals quicklyand provides excellent cambial con-tact. Make one 2 1/2-inch sloping cutat the top of the rootstock and a match-ing cut on the bottom of the scion. Onthe cut surface, slice downward intothe stock and up into the scion so thepieces will interlock. Fit the pieces to-gether, then tie and wax the union.

3. Care of the graft—Very little success ingrafting will be obtained unless propercare is maintained for the following yearor two. If a binding material such asstrong cord or nursery tape is used on thegraft, this must be cut shortly aftergrowth starts to prevent girdling. Rubberbudding strips have some advantagesover other materials. They expand withgrowth and usually do not need to be cut,as they deteriorate and break after a shorttime. It is also an excellent idea to inspectthe grafts after 2 or 3 weeks to see if thewax has cracked, and if necessary, rewaxthe exposed areas. After this, the unionwill probably be strong enough and nomore waxing will be necessary.

4. Limbs of the old variety that are not se-lected for grafting should be cut back atthe time of grafting. The total leaf surfaceof the old variety should be gradually re-

duced as the new grafted variety in-creases until at the end of 1 or 2 years,the new variety has completely takenover. Completely removing all the limbsof the old variety at the time of graftingwill increase the shock to the tree andcause excessive suckering. Also, the sci-ons may grow too fast, making them sus-ceptible to wind damage.

E. BuddingBudding, or bud grafting, is the union ofone bud (attached to a small piece of bark)from the scion to the rootstock. It is espe-cially useful when scion material is limited.It is also faster and forms a stronger unionthan grafting.1. Patch budding—Plants with thick bark

should be patch budded. This is donewhile the plants are actively growing, sotheir bark slips easily. Remove a rectan-gular piece of bark from the rootstock.Cut a matching rectangular piece with abud and piece of bark from the scion tocover this wound. If the rootstock’s barkis thicker than that of the scion, pare itdown to meet the thinner bark so thatwhen the union is wrapped, the patch willbe held firmly in place.

2. Chip budding—This budding method canbe used when the bark is not slipping. A

Whip or tongue graft

downward cut is made at a 45 degreeangle about one quarter through the root-stock. About 1 inch above the first cut, asecond cut is made slicing downward andinward until it connects with the first cut.The cuts removing the bud from the bud

Scion

RootstockChip bud

Patch bud


stick are made just as those in the root-stock, except the lower cut is made about1/4-inch below a bud. Fit the bud chip tothe stock and wrap the union.

3. T-budding—This is themost commonly usedbudding technique.When the bark is slip-ping, make a verticalcut through the bark ofthe rootstock, avoidingany buds on the stock.Make a horizontal cutat the top of the verticalcut (in a T shape) andloosen the bark bytwisting the knife at theintersection. Remove a shield-shapedpiece of the scion, including a bud, bark,and a thin section of wood. Push theshield under the loosened stock bark.Wrap the union, leaving the bud exposed.

Care of buds—Place the bud in the root-stock in August. Force the bud to developthe following spring by cutting the stock off3 to 4 inches above the bud. The new shootmay be tied to the resulting stub to preventdamage from the wind. After the shoot hasmade a strong union with the stock, cut thestub off close to the budded area.

F. Plant Tissue CultureTissue culture is a mass of undifferentiatedcallus tissue growing on an artificial me-dium, separately from the plant from whichit originated. Size increases by cell division.After about 4 to 6 weeks, the mass of cellsis large enough to divide into sections andreculture to produce additional tissue cul-tures. This procedure is usually done in alaboratory or under laboratory conditions.A tissue culture can be started from a vari-ety of plant parts that have cells capable ofdividing. Usually tissues near the vasculararea of stems and roots proliferate best, butcultures have been started from fruits, en-dosperm, pollen, and embryos. To readmore about this exciting method of propaga-tion refer to books in your local library.

Further Reading

BooksThe Virginia Master Gardener Handbook, Virginia

Cooperative Extension Service, VirginiaPolytechnic Institute and State University,Blacksburg, VA 24061.

The Nevada Master Gardener Handbook,University of Nevada Cooperative Extension,phone 702/784-4848.

Wilkins, H. M. 1988. Plantwatching: How PlantsLive, Feel, and Work. MacMillan Co., New York,NY.

Wilkins, H. M. 1988. Plantwatching: How PlantsRemember, Tell Time, Form Partnerships, andMove. Facts on File Publications, New York, NY.

Booklets and PamphletsUniversity of Idaho ExtensionCIS 869 Controlling Sunscald on Trees and VinesPNW 496 Grafting and Budding Plants to

Propagate, Topwork, RepairCIS 866 Homeowner’s Guide to Fruit Tree

FertilizationCIS 881 Success with Very Small SeedsPNW 121 Nutrient Disorders in Tree Fruits (online

only)PNW 164 Propagating from Bulbs, Corms, Tubers,

Rhizomes, and Tuberous Roots andStems

PNW 151 Propagating Herbaceous Plants fromCuttings

PNW 170 Propagating Plants from SeedCIS 1043 Selecting Grape Cultivars and Planting

Sites in IdahoPNW 400 Training and Pruning Your Home

Orchard

T-bud

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Published 1998. Revised 2008.

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idaho master gardener handbook chapter 4

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