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1Agaves in the Garden Jack Kelly Commercial Horticulture Agent A Guide to Selecting, Growing and Enjoying AgavesAZ1336Jack KellyCommercial Horticulture Agent
2Agave 200 - 250 species identified and described Native to Western U.S., south through Mexico, Central America and the West IndiesThere are between 200 and 250 identified and describes species. Early attempts at classifying this diverse group of plants was based on leaf forms. Since many were being grown (both indoors and outdoors) in Europe and other lower light areas of the world, this method was not reliable due to less-than-ideal conditions. Leaf sizes, colors and shapes are much different under natural habitat conditions than glass house and lower light conditions.Later plant taxonomists relied on flower types and observations of plants in the wild for classification. Howard Scott Gentry published ‘The Agaves of Continental North America’ in 1982 in which he organized this diverse genus by floral characteristics. This is also difficult for taxonomist as many species bloom only after many years of growth.Agaves are found throughout north America, south through Mexico, the Caribbean and Central America. Many of the more spectacular species are found in Mexico and the warmer areas of their range.
3Grow in area from 0 to 7000ft. in elevation Howard Scott Gentry divided the species into two groupsHoward Scott Gentry spent many years exploring Agaves in their native habitats. This resulted in his authoring ‘The Agaves of Continental North America’, the definitive reference on agaves.
4Those with a spike inflorescence (54 species) Those with a panicle inflorescence (82 species)There are two basic types of inflorescences of Agave. The first being ‘spikate’ and commonly grown species would include A. parviflora, A. villmoriniana and A. toumeyana. The other type of inflorescence is ‘paniculate’ which resembles a candelabra. The most commonly grown species with this type inflorescence would be A. americana or the classical ‘Century Plant’.
5The inflorescence of agave is often used to identify and classify the species. The inflorescence (A) is the typical spicate form of the flower stalk; photo (D) is the classical panicle form. The spicate form is unbranched and the flowers are directly attached to the main stalk. The paniculate form has a branched inflorescence. The other photos (B,C, and D) are intermediate forms of A and B. Species with a spicate inflorescence may hybridize with paniculate inflorescence species..Types of Inflorescence (Courtesy of Arizona Press: Agaves of Continental North America)
6Agave Basics Plant in well-draining soil Provide adequate light - many species prefer partial sun or filtered lightIn-ground culture of agaves is similar to that of container growing. The plants are most active during the warmer months and will often languish if planted during the colder months in winter.Careful selection of a planting location that affords some relief from the direct sun is desirable. Not all species require shade, so visit arboreta, and botanical gardens in your area to observe the various species tolerance to full sun culture
7Carefully choose a micro-climate Best when planted during warm weather to aid in root developmentChoose a micro-climate that is free of hard freezes and receives sunlight during winter. During summer, most species will benefit from ‘dappled shade’ or planting on the east side of buildings.Since agaves are more actively growing during warm weather, planting during the coldest moths of winter (December-March) should be avoided. The exception to this guideline would be any species that is cold hardy and is container grown. Agaves should be kept on the ‘dry side’ and watered about once a month if there is a prolonged dry spell during winter; during summer once a week irrigation is adequate to maintain the health and appearance of the plants.
8Use organic amendments carefully -. too much can interfere with proper Use organic amendments carefully too much can interfere with proper drainage and lead to rottingProtect from direct sun when planting nursery grown plants. Plant at the same orientation as grown in the nurseryWhen planting (either bare root or from containers), try to re-orient the plant to the same direction that the plant was grown. Like many succulents they can and will sunburn.Bare root plants will benefit from protection from direct sunshine by using either cheese cloth or shade cloth (20%) until the plant is established. This establishment period may be from a few weeks in spring and fall to up to several months in summer and longer in winter.Planting holes should be the same as you would use for desert shrubs, i.e., a shallow wide hole that is no deeper than the rootball and several times the diameter of the rootball. Use organic amendments sparingly, and add pumice or perlite if the soil drains slowly or poorly.The small plants that you buy in the nursery or convenience store may grow up to be very large (up to 5 ft. wide) specimens. To avoid problems use reference books, your local Cooperative Extension and knowledgeable nursery professionals to determine expected mature sizes and space the plants accordingly.
9Know the mature size of the plant and space accordingly Be aware of spines especially in areas of pedestrian trafficThis slide shows A. weberi planted near a sidewalk. The plant was only 6 inches in diameter when planted and now has outgrown its space. Since this variety has a terminal spine on each leaf, these spines can be trimmed off reducing the chances of injury to people. However, careful planning and a little research into the species mature sizes can reduce or eliminate people/plant problems.
10Remove any damaged roots from. field grown plants and allow to Remove any damaged roots from field grown plants and allow to dry for several days in the shadePlant in a shallow wide hole with a minimum of organic amendment in the backfillWhen purchasing collected (from the wild) or bareroot (nursery grown) plants, remove any damaged or broken roots. These roots will typically die off and a new set of roots will be initiated by the plant. If the plants are freshly dug from a growing bed, allow several days for the roots to ‘callus over’ in the shade before planting.
11Water thoroughly after planting and determine the irrigation schedule Do not use organic mulches; use decomposed granite or rockKeep water off of wide-leaved agaves to prevent spotting of the foliageWater in thoroughly to insure that the soil has made contact with the roots and that residual air pockets are removed. Water once a week initially, and after establishment this interval can be reduced and fine tuned.Do not use organic mulches such as bark or compost. Use gravel or decomposed granite which will not retain water and lead to rotting of the lower leaves or the entire plant.
12Container GrowingChoose appropriate varieties such as A. victoriae-reginae, A. parryi var. pattoni, A. fernandi-regis, A. macroacantha. Larger species require larger potsSome species grow quite large and are not suited for container culture. Visit nurseries and botanical gardens to see the various species and to determine the mature size of the plants. When grown in containers, larger species will typically be smaller due to the constriction of their roots. The smaller species are better suited to container culture and can develop to their normal mature size and not require re-potting for many years.From Left to Right: A macroacantha, A. victoriae-reginae, A. parryi var.pattoni
13Use a quick - draining medium Use slow release fertilizer or liquid fertilizers such as Miracle - Gro™, Peter’s™, etc.A rapidly draining medium is essential for successful agave growth. Avoid ‘heavy’ poorly draining soil mixes. If loose friable soil is not available, purchase commercially prepared potting soil and add approximately 20-25% pumice or perlite.Soluble fertilizers are very safe and will not burn when used according to the label. Many agave fanciers use readily available soluble fertilizer at half the recommended strength with each watering during the growing season. There is no need to fertilize during the coldest months of winter as the plants are not actively growing during this period. Extended release fertilizers such as Osmocote™ may be used in place of soluble fertilizers.Always follow the label instructions to avoid problems and misuse of these products.
14Under-pot to aid in soil drying out between waterings Plant slightly high in container with lower leaves above the soilTo grow properly, containerized agaves require quick draining soil mixtures to prevent waterlogging and subsequent rotting. Fertilizers may be used regularly through the growing season (warm months), however, Agaves will live for years without supplemental fertilization.Since many species are native to woodlands, grasslands and other areas where the plants are given some level of protection from direct sun, locate your plants in areas where they will receive full sunshine for most of the day and light shade during the afternoons.Re-potting may be needed every 3-4 years, Be sure to use containers that have tapered sides so the plants can be removed more easily and the pots re-used.
15Plant in clay containers and water regularly Choose ‘ideal’ location in partial sun to place containerRe-pot every 3- 4 yearsClay containers aid in drying the soil out more quickly than non-porous containers such as glazed ceramic or plastic containers. Always make sure that there are drainage holes in any container you use.The ideal location may vary by species but as a general rule, most agave species will flourish in full sun (8 hours./day) and afternoon shade.Although container grown plants have their roots constricted, they will not be adversely affected by being grown in containers. You should, however, plan on re-potting every 3-4 years or when the plant has completely filed the container or the plant begins to crack clay pots or rip plastic containers.
16Light ExposureMost agaves prefer filtered light or be accompanied by small native shrubs that will provide some filtered light.Most, but not all agaves are prefer filtered light and will grow well under a Palo Verde (Parkinsonia spp.)or another thinly foliated tree, adjacent to shrubs or a in an area that receives afternoon shade. Plants grown in such situations will be slightly taller and wider than those grown in full sun.
17Growing and Rooting Medium 50% Pumice% Sphagnum Peat Moss/Compost20 -25% SoilAgaves require very good drainage. To accomplish this, use a soil mix that contains 50% pumice (volcanic rock). If pumice is not available, perlite, which is readily available, may be used as a substitute. The soil portion of the mix should be a rich organic soil. Avoid clay soils which may contribute to slow or poor drainage. This is just one of many soil mixes used by growers and fanciers. The critical element is that the soil drain quickly yet retain some moisture. Do not use manure in the soil mix due to a potential build-up of salts.
18Agave speciesAgaves are an incredibly diverse group of plants and fill an important niche in and low water use plant palette. They are unrivaled for their striking foliage, their perfect form and toughness.
19A. americana is a commonly-grown species and is a large plant (up to 8 ft. in diameter). It is reliably cold hardy to the mid - to - low twenties (F), offsets prolifically and flowers after many years. It is particularly susceptible to Agave Snout Weevil attack.A. americana
20A. americana ‘Medio Picta’ A. americana medio picta is a a large (>4 ft.) plant at maturity. It is cold sensitive and may be damaged at temperatures in the mid twenties to the teens. It is prolific, offsetting freely, and will reach mature size in a about years. The damage leaf at the base of the plant is from freeze damage the previous year.A. americana ‘Medio Picta’
21A. colorata is a large species that grows to four feet or more in diameter. It characteristically leans toward the sun and vertical specimens are rarely seen. It is reliably cold hardy to 25 degrees F. .A. colorata
22A. durangensis is cold hardy to about 10 degrees F, and is a large plant with a mature size of ft. tall and ft. wide. At the Pima County Extension cactus garden in Tucson, the specimens are approximately inches in height and width prior to blooming. It offsets sparingly.A. durangensis
23A. victoria-reginae forma nickelsii A. victoria-reginae forma nickelsii. It is very slow growing and will reach a mature size of 18 inches wide in about 15 years. It prefers filtered light and is hardy to about degrees. The name A. ferdnandi-regis is an erroneous name but it is the name under which it is referred to in the ornamental horticulture trade.A. fernandi regis (hybrid of A. asperirima x A. Victoriae reginae forma nickelsii
24A. geminiflora is one of the newer agaves in trade A. geminiflora is one of the newer agaves in trade. The plants are basically spineless with a very small (1/4 inch) terminal spine. The leaves are narrow, flat and have small thread-like filaments on the margins. Mature size is approximately 2-3 ft in diameter and height. The plant does not offset and most plants are grown from seed. Selections have been made and A. geminiflora is currently being propagated by tissue culture.A. geminiflora
25A. havardiana is a medium sized agave that is cold hardy to about 0-5 F. It will grow and appear more attractive when given some light shading or filtered light.It would greatly benefit if grown under an open-canopied tree such as Mesquite (Prosopis spp.) or Acacia spp. Mature size is 2 wide and 2.5 feet tall.A. havardiana
26A. leopoldi is thought to be a naturally occurring hybrid of A A. leopoldi is thought to be a naturally occurring hybrid of A. schidigera and A. filifera. Not reliably cold hard, it may require frost protection to keep it damage free. It makes a very attractive potted, patio plant. When grown in direct sun, it often gets a reddish tone to the outer leaves, once the light intensity decreases in fall and winter, it returns to its green color.A. X leopoldi
27A. lophantha, which used be called A A. lophantha, which used be called A. univittata is a commonly grown species. It is very prolific and is often a plant that is ‘given’ to someone rather than being purchased from a nursery. It is prone to sunburning and should be given afternoon shade to prevent this problem.A. lophantha
28A. macroacantha can grow to three-four feet in diameter but maintains a two ft. diameter in a container. It is not reliably cold hardy and will show freeze damage at degrees. Its striking blue color make it a favorite of many collections, especially in freeze-free areas . It is prolific and produces numerous offsets.A. macroacantha
29A. murpheyi is a commonly grown species and typically grows to ft. tall and ft. across. Since it rarely sets seed, this species is grown from bulbils which are small clonal plantlets found on the inflorescence. It is cold hardy to at least 25 degrees. It is closely associated with native American ruins and is thought to have been grown from Mexico north to central Arizona lending to theory that it was used as a food and fiber source and traded by native American cultures.A. murpheyi
30Agave palmeri is a medium sized (up to 3-4 feet in diameter) species that is cold hardy to 10 degrees (F). It’s leaf shape and form is quite variable and ranges from long slender leaves to more stout leaves as shown in this photo.A. palmeri
31A. parryi var. huachucensis A. huachucensis is an Arizona native species that varies in color from green through blue-gray and is a very large species that may grow up to 4 ft. or more in diameter. Selections of this plant have been made over the years and result in plants that look like overgrown artichokes.A. parryi var. huachucensis
32A. parryi var. huachucensis A blue-green selection of A. parryi huachucensis, grown in full sun. The species is quite variable and ranges from medium green through silvery gray.A. parryi var. huachucensis
33A. parryi patoni is a small to medium (14-18 inch) diameter cold hardy species that will offset profusely. With partial shade it develops a pleasing bluish color. Sometimes called A. parryi patoni compacta. It makes an excellent potted plant.A. parryi patoni
34A. parryi truncata is also a very popular variety and will grow to about inches in diameter. It is cold hardy to about 15 degrees and offsets readily. Given more light than this specimen has received, the plant will be tighter (more compact) and leaves will be more incurved.A. parryi var. truncata
35This is an increasingly popular species This is an increasingly popular species. A selection called “the Huntington Clone’ is particularly sought after because of its perfect form and medium size. The Huntington Clone is being propagated utilizing tissue culture and will soon be readily available in the nursery trade.A. parryi var. truncata
36A. parryi var. truncata ‘Huntington Clone’ This is the very famous and sought after clone of A. parryi truncata. The story goes….that while on a collecting trip to Durango, Mexico Dr. Gentry found a spectacular clone of A. parryi truncata which he sent to the Huntington Arboretum in It is from this clone that one of the most sought after plants originated. The original plant flowered in June Clone #10570 is the most truncate of those collected by Dr. Gentry and this clone is referred to the ‘Huntington Clone’. It makes a spectacular potted patio plant or addition to a xeriscape garden.A. parryi var. truncata ‘Huntington Clone’
37A. parviflora is an Arizona native agave that grows in a small area along the Arizona/Sonora border. Its mature size is 6-8 inches in diameter and 4-6 inches tall. To truly appreciate the beauty of this plant, it must be watered sparingly. It will loose its beautiful form when over-watered. Over-watering may also lead to rotting and pre-mature death of the plant.A parviflora
38A. schidigera Photo Courtesy of Greg Starr A. schidigera is relatively new in the nursery trade. Its mature size is inches in wide and often develops a short stem. It will require light frost and sun protection but will maintain its rosette form under these conditions. It will need frost protection when temperatures fall into the low teens. In the low desert the plant will require regular (once a week) irrigation to survive and look attractive.A. schidigera Photo Courtesy of Greg Starr
39A. toumeyana is an Arizona native species and is quite attractive in the landscape. The species forms small clumps and produces many offsets. A selection of A. toumeyana (A. toumeyana ‘Bella’) is a miniaturized version of this species and has numerous white filaments which gives the plant a white fuzzy appearance.A. toumeyana
40Another photo showing A. parryi in it’s native range in Mexico Another photo showing A. parryi in it’s native range in Mexico. The plants grow in ‘colonies’ that have developed over many years from one individual seedling. The plants are growing in volcanic rock with very little soil and on very rapidly draining sloped areas.
41Agave parryi in northern Arizona Agave parryi in northern Arizona. The flowers which are very striking last for months. Once the plant blooms, that particular plant dies but the offsets take its place and through this process eventually form ‘colonies’. When plants die after blooming once in their lifetime, this is referred to as being ‘monocarpic’. Plants that do not die after blooming and bloom several times in their lifetime are referred to as ‘polycarpic’.
42Agave hybrid: A. scabra X A. fernandi regis This is a man-made hybrid. Many selections have been made from the original seedlings. This particular plant is an open plant approximately 3 ft. in diameter.Agave hybrid: A. scabra X A. fernandi regis
43Same hybrid as the previous slide but grown in full sun The same species as the previous slide but grown in full sun. As expected, the leaves are smaller and the plant is more compact than the shade grown specimen in the previous slide.Same hybrid as the previous slide but grown in full sun
44A. victoria-reginae is also a slow growing , much sought after species A. victoria-reginae is also a slow growing , much sought after species. It is quite variable as to the number of offsets that it produces. Some plants do not produce any offsets and must be seed or tissue culture propagated. It grows to approximately inches in diameter and inches tall. A. victoria-reginae is cold hardy to about 10 degrees F.A. victoriae - reginae
45This species a favorite of most gardeners and agave fanciers This species a favorite of most gardeners and agave fanciers. Some cultivars offset freely while others are solitary and do not make offsets or ‘pups’. It is cold hardy to about 10 degrees. Mature sizes range from 8 inches in diameter to over 18 in. in diameter. Light shading will bring out more of the white markings on the leaves.A. victoriae - reginae
46A. weberi is a large species not suited to small yards A. weberi is a large species not suited to small yards. Its mature size can reach 5 feet tall and 6 feet wide. It is currently being used as a source of juice to make tequilla in Mexico. It is cold hardy to about 15 F. It is being tissue cultured to augment its great demand as a commercial landscape plant and freeway plantings.A. weberi
47Vegetative Propagation This is the fun part of growing agaves. Plant propagation is easy to do and give amateurs as well as professionals the opportunity to multiply their favorite plants.The next series of slides will ‘walk you through’ the propagation process.
48The first step is to allow the plant to dry out for several days The first step is to allow the plant to dry out for several days. This will facilitate the breaking apart of the rootball and the removal of the offsets. When working with in-ground ‘parent’ plants, offsets can be easily removed by using a sharp knife, a shovel or hand pruners.
51Cut back the roots to about 1/4 inch Cut back the roots to about 1/4 inch. This is done for several reasons: first, the damage roots will die and the plant will re-initiate new ones. Second, the offsets are much easier to handle and plant without roots.
52Segregate the offsets by size Segregate the offsets by size. The large and medium sizes will root easier than the very small offsets. The offsets on the right are too small for the average person to handle and propagate without the use of fungicides. Unless the species is rare, discard the smallest offsets.
53These are typically too small to easily propagate. Discard them.
54Dry the offsets in the shade for two or three days and then firmly hold the center of the plantlets as shown and press them into the prepared propagation mix. No rooting hormones are needed. See slide 13 for the propagation mix.Water in thoroughly and place in a greenhouse or an area that gets filtered light such as under a mesquite (Prosopis spp.) or Palo Verde (Parkinsonia spp.) tree.Water regularly but do not over water or allow the soil to become water- logged.For best results, propagation should be done during the warmer months (May - September).
55Roots should develop in about 21 days if the plants are propagated during the summer months. If propagated during late fall or winter, rooting is delayed and the chances of the offset rotting before rooting is greater.
56Octopus Agave Agave vilmoriniana Source of ‘bulbils’ for propagation Octopus Agave (A. vilmoriniana) is perhaps one of the easiest agaves to propagate. The plant is without spines and the foliage is soft. The species does not form rhizomatous offsets and is grown from bulbils and occasionally seed. This slide shows a mature inflorescence covered with bulbils which are the source of new plants. The bulbils are genetically identical to the parent plant.Source of ‘bulbils’ for propagation
57A. vilmoriniana bulbils Be sure not to remove the basal plate at the base of the bulbil. If the basal plate is removed the bulbil will not root. No rooting hormones are necessary for successful rooting. Often, the bulbils will have adventitious roots that will further root out and help the bulbil establish quickly.
58Unrooted bulbil just removed from a flower stalk on left (note adventitious root in the center of the basal plate). On the right is a rooted bulbil after 21 days in the rooting medium.
59When working with offsets of larger species, wet the area and then carefully lift the offset (‘pup’) out of the ground with a shovel or by tugging gently on the offset. If it’s difficult to lift the offset out of the ground, loosen again with a shovel and try again. Remove and trim any damaged roots. Dry in the shade for several days and then plant as you would any bulbil or offset. If the offset is not properly dried, the chances of rotting are greatly increased.
60Offset showing the rhizome connecting the offset to the parent plant Offset showing the rhizome connecting the offset to the parent plant. The offsets or ‘pups’ are formed underground from the adventitious buds along, or at the end of the rhizome. They are genetically identical (a clone) to the parent plant.
61Seed Medium50% Pumice (Perlite can be used as a substitute for pumice)25% Sand20% Sphagnum Peat Moss5% VermiculiteTop dress with 1/4 inch of pumiceSeed propagation is a popular method of mass producing species that flower and set seed or do not make offsets. The medium is a rich mixture that drains quickly, has moisture holding capacity, retains nutrients, and has good aeration. The grower is trying to mimic nature where seed often falls to the ground and germinates in a pocket of rich leaf litter or compost.It is through seed propagation that ‘new’ selections are often available after examining thousands of seedling and keeping a keen eye out for one that is superior to those currently available on the market.Scatter the seed over a flat containing the seedling soil mixture and top dress with pumice. Water thoroughly and keep seed flat damp. Germination will take place within 1 week. The seedling will appear as a stand of rye grass and will start forming typical rosette leaves in several weeks. Some seedling plants will even develop a characteristic terminal spine. Germination is rapid when temperatures of the soil and air are above degrees.Transplanting can be done as soon as the seedlings are large enough to handle (4-6 months). Survival is higher and losses due to fungi and rot organisms are lower with larger seedlings. Transplant into growing mix (slide 13).
63The SpoilersAlthough relatively easy to grow, agaves do have several pest that can be devastating.
64The most well-known and devastating insect pest is the agave snout weevil (Scyphophorus acupunctatus) which causes the collapse and death of agaves plants. This specimen of A. americana is beyond help and is doomed.
65A bottom view of an agave destroyed by agave snout weevil A bottom view of an agave destroyed by agave snout weevil. The larvae will be found in the rotting inner tissue in the center of the plant.
66Agave Snout Weevil Adult Approximate Size 1/2 inchThe adult agave snout weevil is about 1/2 inch long is black or dark brown. The adults are rarely seen but occasionally can be found in and around dead and dying plants.
67Agave Snout Weevil Larvae The larvae of the agave snout weevil feed in the inner core of the plant (bole). Secondary rot organisms also enter the plant and lead to the rapid decay and loss of the plant. Little is known about the biology of the weevil but since they are active during warm weather, applications of a systemic insecticide drench in spring may help to prevent infestations. Do not re-plant agaves in the same area as those that died as a result of snout weevil infestation.Actual Size Approximately 1/3 inch
68Damage caused by a minute plant bug (Caulotops barberi) This damage is caused by a minute true plant ‘bug’. The scaring of the leaves is the result of scars from the piercing /sucking mouth parts of the pest. The problem is more prevalent on plants that are water stressed and in neglected conditions. A spray of a broad spectrum insecticide is an effective control. There are no known biological or non-chemical controls.Healthy plants which are adequately fed and irrigated will be more likely to ward off serious damage.Damage caused by a minute plant bug (Caulotops barberi)
69Many agaves are damaged a freezing and below freezing temperatures Many agaves are damaged a freezing and below freezing temperatures. Damage is often cosmetic and the bole ‘heart’ often recovers and grows new leaves. Damage can by prevented by covering the plants with any non-plastic sheeting and placing an electric bulb (40-60 watt) under the covering. Be sure that the light bulb is not directly touching the covering or the plant. As soon as temperatures moderate in morning to above freezing, remove the covering and light bulb. The extent of freeze damage is dependent upon the duration of the freeze, the condition of the plant (such as over-fertilization late in the fall), the hardiness of the species, and the location of the plant. If you live in a cold area , attempt to plant agaves where there is radiated heat, such as against a west- facing wall, or a sheltered area on a patio. During severe cold, containerized plants can be moved indoors until after the cold spell is passed.Freeze Damage on Agave
70Agave damage caused by over zealous pruners Agave damage caused by over zealous pruners. Agaves should not be pruned. After a severe freeze, some lower leave may need to be removed (for appearance) but over-zealous pruning like this should be discouraged.
71F. A. Q.The following a list of frequently asked questions and responses.
72Commonly Asked Questions Q: Do all agaves die after they bloom?A: Most agaves die after blooming (monocarpic), however several species such as A. braceosa are polycarpic and may bloom several times during their life.The rosette that flowers will die if the inflorescence comes from the center of the plant. The off setting types will have other rosettes that live, but the one that flowers will eventually die.
73Q. Once a plant gets infested by Agave Snout Weevil, can the plant be saved? A. Typically there is no control that will save the plant. The rot organisms have a perfect environment (water, warmth and sugar) for rapid growth.
74Q. What are the differences between agaves and yuccas? A. Yuccas bloom almost every year, agaves do not; yuccas have typical bell shaped blooms, agaves do not have true petals (they have tepals - petals and sepals that are nearly indistinguishable); yucca flowers are white, agave flowers may be white, pink, red or yellow.All yuccas except Yucca whipplei will continue to live after blooming. Yuccas have a superior ovary while agaves have an inferior ovary Yuccas do not have showy teeth along their leaf edges while many agaves do.
75Q. How often should I water my agave plants? A. Like most other plants, it depends on the weather and the time of year. Agaves will withstand long spells of drought (especially in winter) and will require times a week watering during the hottest months.They are capable of standing prolonged dryness, but look better with regular irrigation. If you have particularly sandy soil, irrigation frequency is increased; on heavy clay soils the frequency will be decreased.
76Q. How often do I fertilize my agaves? A. Agaves can survive on low fertility soils but will grow more rapidly and look better with regular fertilization during the spring through fall. No fertilization is recommended during the winter and cooler month.
77Q. How long do agaves live? A. Agaves can live for many years (more than 25 years). The longevity depends on the species. Some species such as Octopus agave (A. vilmoriniana) live about 5-7 years, bloom and die. Some parryi species live more than 25 years. If the plant is well cared for the longevity will be greater than a poorly maintained plant.
78Valuable additions to your library: Agaves, Yuccas, and Related Plants, A Gardener’s Guide, Mary and Gary Irish, Timber Press, Portland Oregon. ISBN Cost: Approximately $35 USAgaves of Continental North America, Howard Scott Gentry, University of Arizona Press, Tucson, Arizona, ISBN Cost: Approximately $125 US hard bound, $35 US soft boundAgaves, Yuccas and Related Plants-a Gardener’s Guide is an excellent reference for both amateur and professional agave fanciers and growers. It is written in an easy-to-understand style, has many color plates and illustrations, and practical information.Agaves of Continental North America is a reference for the very serious agave student. It very technical but is probably the most inclusive reference on the genus Agave.It makes an excellent historical reference and gives locations throughout North America of the species described in the book.
79Agave photos used by permission Mary Irish and Greg Starr CreditsMary and Gary Irish, from Agaves, Yuccas and Related Plants, A Gardener’s Guide, Timber Press, Portland, OregonGreg Starr, Starr Nursery, Tucson, ArizonaSpecial Thanks to Dan Bach, Bach’s Greenhouse Cactus Nursery, Tucson, ArizonaAgave photos used by permission Mary Irish and Greg Starr
80This information has been reviewed by university faculty May 2004 Questions,Comments?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 & Life Sciences, The University of Arizona.The University of Arizona is an equal opportunity, affirmative action institution. The University does not discriminate on the basis of race, color, religion, sex, national origin, age, disability, veteran status, or sexual orientation in its programs and activities.Persons with a disability may request a reasonable accommodation, such as a sign language interpreter, by contacting DRC (Disability Resource Center) at (V/TTY).Requests should be made as early as possible to allow time to arrange the accommodation.This information has been reviewed by university faculty May 2004cals.arizona.edu/pubs/garden/az1336.ppt