Cooperative Extension

Issued in furtherance of Cooperative Extension work, acts of May 8 and June 30, 1914, in cooperation with the U.S. Department of Agriculture,James A. Christenson, Director, Cooperative Extension, College of Agriculture and Life Sciences, The University of Arizona.The University of Arizona College of Agriculture and Life Sciences is an equal opportunity employer authorized to provide research, educationalinformation, and other services only to individuals and institutions that function without regard to sex, religion, color, national origin, age, Vietnamera Veterans status, or disability.

Cactus, Agave, Yucca and Ocotillo

10/2001 AZ1225THE UNIVERSITY OF ARIZONA

COLLEGE OF AGRICULTURE AND LIFE SCIENCESTUCSON, ARIZONA 85721

Jack KellyAssistant Agent, Commercial Horticulture

Rob GrumblesAgent, Agriculture & Natural Resources

(based on material originally written by BoyceFoerman, retired Horticultural Agent)

This information has been reviewed by university faculty.

ag.arizona.edu/pubs/garden/az1225.pdf

CactusCactus can give that authentic touch of native dignity

that seems to legitimize and complement Arizona desertlandscapes. They make excellent specimen plants orstriking accents. The Cactus family numbers over 2000species. Typically cactus are devoid of leaves and haveswollen stems, spines or scales. All cacti are native tothe New World and are found from North America tothe southern tip of South America.

The thick waxy coated stems of these perennial herbsare quite resistant to moisture evaporation, which givesthem considerable drought tolerance. Desert cacti areleafless; however, most have spines. Photosynthesis(food production for the plant) occurs within the greenouter cortex of the stems, and moisture reserves arestored in the internal part of the stems, sustaining theseplants through prolonged dry periods of desert climates.Structural support for cactus plants is provided by in-ternal fibrous or woody skeletal forms. Most cacti havetapering tap roots that anchor the plant and fleshy lat-eral roots close to the soil surface that extend outwardfor several feet in all directions. These absorb and storemoisture and nutrients. The rose-like flowers of cacti,which are contrastingly delicate and beautifully colored,produce edible although sometimes not too palatablefruit.

Transplanting is usually necessary since cacti seldomoccur naturally in desired landscape locations. Althoughthey can be transplanted year-round in southernArizonas lower elevations, quicker reestablishment canbe expected from March through October. Warmer tem-peratures favor active root growth and, consequently,quicker establishment of the transplant.

Transplant cacti in their original directional orienta-tion. This is very important! The south and southwestsides of these plants become toughened and resistant tosunburn. The more tender north or east sides are likelyto sunburn and scar and may rot if exposed to the in-tense hot sun. Before transplanting, mark the north sidewith chalk, ribbon, etc., and replant with that side again

to the north. To aid in protectingagainst sunburning, the newlytransplanted plants may be cov-ered with a piece of shade cloth.The shade cloth should be left onuntil signs of new growth and es-tablishment occur.

To remove cactus from itsoriginal location, first cut theshallow roots by forcing asharp shovel blade to itsdepth into the soil completelyaround the plant about a footaway from the base. Then,dig under and carefully pry and lift he plant out of theground. Try to minimize injury to the plant. When dig-ging ocotillo and saguaro cacti, care should be taken notto damage the corky area between the roots and aboveground parts of the plant. Allow any loose soil to fallaway from the roots.

Prune off any damaged roots with sharp, clean prun-ers. Then, prune back the remaining lateral root stubs,leaving them five to ten inches long. Dust these cuts andother wounds immediately with powdered sulphur tolessen chance of infection and hasten callousing (heal-ing).

Cactus transplants should then be placed in a shaded,open area for one to two weeks after digging to allowthe fresh-cut roots to heal before transplanting. Replantcacti in dry soil and do not irrigate until new growthappears at the apex (tips) of the plant which may takeseveral weeks.

Large cacti such as saguaro are best transplanted by areputable nursery or specialized cactus company. Sincethe plants can weigh up to 100 pounds per linear foot,even a modest 6 foot saguaro can weigh too much for

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the homeowner to handle withoutspecial equipment.

Smaller saguaros (up to 3 feet)can be successfully transplantedwithout special equipment. Re-quest written planting and care in-structions from the supplier andfollow them carefully. Since theplants are slow to reestablish, thebuyer should request a two-yearguarantee from the nursery or sup-plier. Customers should ask forwritten instructions if possible. Pur-chase native cacti from reputable nurseries and fol-low their written instructions to reestablish properly.

Well drained sandy or gravelly loam soils are bestfor most cacti. If heavier, tighter soils are used, spadein 1/3 to 1/2 by volume of washed sand plus somecrushed granite, fine gravel, etc., and mix it well withthe upper foot of original soil.

Raised (slightly mounded) open locations should beprovided for transplanted cacti. Avoid locations wherewater is likely to collect, and keep the soil overly wet.Also, avoid planting against a south or west wall. In-tensified and reflected sunlight may burn the plants.Dont crowd cactus plantings. Allow space for air tocirculate freely around them. Smaller cactus varietiesthat normally grow under native shrubs should be pro-vided appropriate shading. Never nail anything to acactus as this may lead to scarring, disfigurement or apoint of entry for pathogens.

Care of cacti is minimal but important. The soilshould not be cultivated or otherwise disturbed in aradius of several feet around cacti, lest their shallowlateral roots be injured or disturbed. Light surface rak-ing is permissible for the sake of appearance. Crushedgranite, natural stone or organic surface mulches maybe used over cactus beds for decoration and protec-tive effect. Dont mulch with any materials that re-flect or intensify light. Dont cover root zones withplastic sheets.

Irrigation typically is notnecessary for native cactusplants except for critical periodsof prolonged summer drought.Irrigation is a criticalconsideration in the culture ofnative desert plants. Neverpuddle water around the base ofcacti for any period of time.Enough moisture is vitallynecessary, but excess water canbe particularly hazardous toplant survival. Soil surfacesshould slope moderately away

from these plants, so water will not collect at the baseof their stems. Plants may succumb to rots. Unless youknow for sure cactus is suffering from lack of moisture,dont irrigate it! Check the soil moisture at rooting depthbefore subsequent watering to avoid overly wet soils.Irrigate sufficiently to keep the soil in the rooting areaslightly damp after transplanting and until new rootdevelopment begins and the plant becomes established.Established younger plants usually need not be irrigatedmore than about every two weeks during southernArizona summers and older plants probably only onceto twice each month. With normal amounts of rainfall,no irrigation will be needed during the cooler seasonfrom late fall until early spring. Wet soils can beparticularly detrimental and even more likely topromote rots during cooler seasons when plants aredormant (not growing). Dont over-irrigate at any time,if in doubt, dont. Most desert plants are more tolerantof too little soil moisture than too much.

Fertilization is generally not necessary; however, lim-ited cautious application of a well-balanced fertilizerearly in the growing season will stimulate growth andvigor. Stimulated growth of cacti in the fall by fertiliza-tion or irrigation makes them more susceptible to win-ter freeze injury. No irrigation or fertilizer is requiredduring the winter months.

Agave, Yucca and OcotilloAgaves are one of several types of succulent (high

moisture content) plants. They typically have thickfleshy leaves and depending on the species may havenumerous spines on the tips or margins of the leaves.Some may have no spines at all. The century plant isthe most commonly grown in local landscapes; however,there are numerous other agaves equally appropriateand often more desirable for specific desert landscapeuse. Actually considerable variety in size, color and formare available within this interesting family of desert-tolerant succulents. Many varieties of agave die soonafter flowering, however, some varieties will produceoffsets around the base of the original plant which willdevelop and replace the original plant. Some varietiessuch as Octopus agave (Agave vilmoriniana) producesmall plants (bulbils) onthe flower stalk; that canbe removed and easilyrooted.

Yuccas are also naturalsfor any Southwest desertscene. Their characteristicprofiles offer aestheticcontrast when appropri-ately displayed in desertlandscapes. Yuccas, un-like agaves will bloom

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year after year and the plant willnot die after blooming. Many yuc-cas have sword-like leaves, and atmaturity may either be smalltrunkless plants or have largestems or trunks. Here too, there ismore variety than the average gar-dener would expect. Growth ofyuccas occur at top and center ofthe plant. As their older leaves ma-ture and hang downward, theplant depicts a rustic shaggy ap-pearance.

Ocotillo is another unique native desert plant thatlends striking accent with its low-branching, leafy, whip-like canes topped with bright orange-red flowers. Oco-tillos can grow to 15 feet in height and as wide. They aretypically leafless most of the year, but profuse leafing ofthe canes follows periods of sufficient soil moisture.During periods of drought, these curious plants shedtheir leaves to reduce evaporative loss and conserveplant moisture. Widely adaptable to landscape use, oco-tillos are right at home in the desert Southwest.

Transplanting of these desert plants can also be donethe year around with knowledgeable care, but greatestsuccess is achieved during March through May. Trans-plant to the original growing depth and, as with cacti,in their original directional orientation. The originalsouth side of the plant, which has become more heatand sunlight-resistant, should again face the hottersouthern direction. Well drained sandy or gravelly loamsoils with light to moderate amounts of organic contentfavor root development of these desert plants. To helpprevent the newly transplanted ocotillo from falling overor blowing down in a storm, large stones may be placedoverthe root area (2-4 inches from the trunk). Sunny,open, unrestricted locations and those where surfacewater does not collect are best. Some degree of growthset-back is to be expected. Properly transplanted, how-ever, natural desert plants reestablish themselves fairlysuccessfully.

Most yuccas and agaves can be dug, the injured anddiseased roots pruned off, and transplanted immediatelyor held in shaded, open-air storage for a few days toallow root cuts to heal. Its not necessary, norrecommended, that the tops of any cacti, agave, yuccaor ocotillo plants be pruned back when transplanting.Agaves and yuccas benefit from shade cloth draped overthe transplanted plants and removed at first signs ofestablishment and growth. Be patient with transplantssome may take up to a year to recover and reestablishin their new locations. As an alternative, many yuccaspecies are container grown and available from specialtynurseries.

Fertilization with a well-balanced plant food in lightto moderate amounts will usually help stimulate plantgrowth and vigor. However, do not apply fertilizer tonewly transplanted plants. When using fertilizers, ap-ply them evenly to the soil surface over the rooting areaand water it into the soil with an early summer irriga-tion. Dont risk over-fertilizing. As with irrigation - if indoubt, dont. Remember, these plants survive in natureon naturally-occurring fertility.

PestsPests of cacti are not so numerous as they are serious.

Among the most hazardous are people. Vandals andwell-meaning, over-zealous, but uninformed gardenersoften cause needless damage.

Spider mites on yuccas, mealy bugs on stems and rootsof various cacti, cochineal scale on prickly pear cactus,the cactus longhorn beetle on cholla and prickly pearand pocket gophers and ground squirrels on desertplants are in general the most common insect and ani-mal pests. The agave may be attacked by the agave snoutweevil. Damage to agave foliage can result in scarringand potential entry of rot producing organisms, so careshould be taken when working with agaves. Never re-move healthy foliage, and never prune agaves. Wood-peckers can do considerable damage to saguaro cacti.Check with a recognized authority for specific controlsfor these pests.

Rots result from various forms of injury. Bacterial softrot (Erwinia carnegiana) is the primary disease of saguaroand control measures include removal of the soft, blackrotting tissue and treating with a solution of one parthousehold bleach to 10 parts water. All tools such asknives should be sharp and sterile. Use a 10% house-hold bleach solution to clean tools. Re-clean tools in thebleach solution after each cut. Take care to remove alldiscolored plant tissue. The best controls are alwaysprevention. The second best is quick healing before in-fection can set in. Powdered sulphur can also be dustedinto the wounds of cacti as a healing aid.

Unless the problem and solution are understood, itmost often is best to do nothing without first seekingadvice from a competent authority or knowledgeableperson.

State Plant Protection Laws are Enforced!Contact the Arizona Department of Agriculture, 1688

W. Adams, Phoenix, Arizona 85007, for specific regula-tions, restrictions, permits, penalties, etc., before diggingand moving any Cacti, Agaves, Ocotillos, Yucca, JoshuaTrees, etc. For your own protection, purchase your trans-plants from a reputable source.

Any products, services, or organizations that are mentioned, shown, or indirectly implied in this publication do not implyendorsement by The University of Arizona.