The Agave Page 01, 02
Agavaceae = Agave Family, Century Plants

Agave albomarginata offsets freely but individual rosettes only have a few long narrow, blue-gray leaves up to 3 ft long, marked with bud imprints. Leaf margins have white dehiscent borders, small white teeth and gray terminal spines. The inflorescence is a spike of greenish-yellow flowers. This plant is said to be cold tolerant and may be a variety or horticultural selection of A. lechuguilla.

left: Agave americana used as an ornamental plant in a traffic island north of Marathon, Texas. This species is probably the Agave most commonly grown as an ornamental plant, and has spread throughout the temperate and tropical areas of the world. Because of extensive propagation, its exact origin is uncertain although it probably came from Mexico. Agave americana was an early introduction to Europe from the New World and was described by LInnaeus in 1753 as the type for the genus. The huge leaves, up to 6 ft long, are an important source of fibre.
 
Agave americana is undoubtably the most tolerant of all the Agaves which explains its wide feral distribution. Specimens even survive in pots or in the ground in the wet winters around London and along the south coast of England. At the other extreme it may be seen planted out in southern Arizona and Texas.
 
left: Seed head, Marathon, Texas. October 2003.

left: A variety of variegated cultivars of Agave americana are available although these are much less hardy than the normal plant.

Agave attenuata (Fox-Tail Agave) at the Desert Botanic Garden, Phoenix, Arizona, mid-April 2006. This is a very distinctive plant with a large rosette of soft green leaves over 2ft long and 5-8 in wide. Leaf tips are soft and edges smooth or very finely serrated so this plant is suitable for planting near walkways. The dense flower spike of cream to yellowish flowers generally curves in a distinctive manner.
 
This species comes from central Mexico and although growing at around 6000 ft, will not stand any significant frost. A blue selected cultivar is available.

Agave bovicornuta (Cow's Horn Agave)
This species will only tolerate a slight frost despite growing at up to 6000ft in the mountains of Mexico. The solitary rosettes can grow up to 6ft in diameter, so make a splendid specimen.

Agave cerulata var. subcerulata
A fine glaucous blue plant, growing in large clumps with narrow pointed leaves bearing widely-spaced small marginal teeth. There are a number of forms and subspecies, differing in leaf colour and the distribution of marginal teeth. The flower stalk up to 12 ft tall bears a panicle of pale yellow flowers.
Seen here at the Desert Botanic Garden, Phoenix, Arizona.
 
 
left: Agave cerulata var. subcerulata photographed in the Boyce Thomson Arboretum, Arizona.
 
Agave cerulata var. subcerulata is native to Western Mexico including Baja California, growing below 3000 ft. It is very tolerant of hot dry conditions.

Agave colorata
A handsome glaucous blue rosette, usually solitary or offsetting sparingly. The leaves bearing bud imprints and some banding are up to 10 in long and 7 in wide. Leaf margins are undulated. The inflorescence is a panicle of yellow flowers.
 
Agave colorata is native to Coastal Sonora, Mexico. It makes a fine specimen for a dry, low desert garden. Flowering at the Desert Botanic Garden, Phoenix, Arizona, mid April 2006.

Agave durangensis forms a large rosette of up to 6ft across. The pale bluish leaves have wickedly spined margins and prominent apical spines.
 
Agave durangensis is native to Durango and Zacatecas, Mexico, growing among rocks at up to 8500 ft. It is moderately hardy to dry and cold conditions. The inflorescence is a panicle of bright yellow flowers.
Photographed in the Boyce Thompson Arboretum, Arizona.

Agave deserti - These Desert Agaves were part of a fine stand of flowering plants in the San Felipe Wash, Anza-Borrego Desert State Park, California in April 1995. Sometimes called the "century plant", in practice flowering occurs after 8 - 20 years. Although all the flowering plants will die, each group of plants at this site had plenty of offset non-flowering rosettes for other years. The leaves of the rosettes are armed with lethal stiff terminal spines, for which one rapidly aquires respect, and sharp marginal teeth.
 
Desert Agave is one of the most drought-tolerant of the 136 species of agave found in north America, and grows on stony terraine from south-eastern California and south-western Arizona to Baja California and northern Sonora.

The starchy core of the plant was baked in rock-lined pits by desert-dwelling Indians to form a nutritious energy-rich staple food, and baked agave can still be purchased in Mexican markets.

Agave funkiana is a clumping plant with linear yellow-green leaves up to 3 ft long. Leaf margins are undulate with small teeth and a prominent, gray terminal spine. A pale or yellowish stripe runs longitudinally along the middle of the leaf. The upper third of the 15 ft flower stem is a raceme of gray-green flowers with prominent bright yellow stamens.
 
This species is native to Hildago, Mexico, growing at 1000-6000 ft. Photographed in the Boyce Thomson Arboretum, Arizona.

Agave gigantensis has a solitary rosette up to 4ft in diameter. The rigid, thick blue-green leaves are marked with bud imprints and have undulate margins with prominent curved teeth. The inflorescence is a 15 ft panicle of pale yellow flowers.
This species is limited to central Baja California, growing from 2000 to 5000 ft. It is a splendid ornamental for a Mediterranean climate and used in its native area for the production of Mescal. Photographed in the Boyce Thomson Arboretum, Arizona.

Agave havardiana - growing in the basin region within the Chisos mountains of the Big Bend National Park, Texas in April 1990. Typically of this species, the plants in this location were growing as solitary rosettes. The annual precipitation is higher and the climate cooler in this region of the park than on the desert floor and these plants were growing in grassland among mixed deciduous and coniferous forest. The flower bud has just started to develop, and at this stage the Apache used to roast and eat the core of the plant.

Agave lechuguilla growing in the Big Bend National Park, Texas mainly on compacted broken limestone in front of Dog Canyon. April 1990.
Agave lechuguilla is one of the principal indicator plants of the Chihuahuan desert, where it grows very freely spreading vegetatively by stoloniferous shoots, which are soft enough to be browsed by javelinas. The stiff, erect leaves are tipped with surgically sharp needles which injure the legs of people or animals that brush against them.
 
After up to 15 year's growth, depending on the annual rainfall, the plant has stored sufficent reserves in its starchy core to flower. This involves production of a flower stalk (left) up to 15 ft tall, although 6 - 10 feet is commoner. After flowering and production of seed, the plant dies.
 
Uses include fermentation of the sap from the flower stalk to make an alcoholic liquor (pulque) from which mescal / tequilla can be distilled. Fibres from the leaves are used to make a variety of woven products such as ropes, mats and baskets.

Agave lophantha is a medium-sized plant, offsetting at the base, with narrow rigid leaves 2ft long and 1-2 in wide forming a rosette with an open appearance. Leaves may have a yellowish longitudinal stripe down their middle and leaf margins have numerous small straight or curved teeth and a gray or brown terminal spine. The 12 ft flower spike carries pale greenish-yellow flowers.
Agave lophantha occurs in the Rio Grande valley, Texas and into Mexico. It can be confused with Agave lechuguilla with which it hybridises. Photographed in the Boyce Thomson Arboretum, Arizona.

Agave macroacantha at the Desert Botanic Garden, Phoenix, Arizona September 2004. This is a tender plant from the Mexican states of Oaxaca and Puebla and will not stand any frost. The decorative rosettes grow up to 16in and offset freely at their base. The inflorescence is up to 6ft tall with greenish flowers.

Agave murpheyi at the Desert Botanic Garden, Phoenix, Arizona. This Agave grows in central Arizona at elevations of up to 3000ft, but its distribution is thought to reflect relics of cultivation as it was used for food. It is still cultivated in Sonora, Mexico. The original distribution is unknown.
 
The 2ft lanceolate leaves have small brown marginal teeth, crossbanding and a clear bud imprint. They become concave towards their ends. The 12ft tall panicle of yellow-green flowers produces a profusion of bulbils.
 
left: Agave murpheyi near McGraw, Arizona.

Agave ocahui var. ocahui (Ocahui, Amolillo) has stiff, smooth, dark green leaves 10-20 in long, with a dehiscent brown border but no marginal teeth and a weak, flexible spine. The rosette generally remains solitary. The decorative 10 ft spikes of pale yellow flowers are quite distinctive.

left: Agave ocahui is native to moderate elevations in north-eastern Sonora, Mexico. It is said to withstand some frost in dry climates and is widely grown as an undemanding ornamental plant.
 
The leaves are a source of strong fibres (ocahui=cord) and also contain the saponin smilagenin which can be used as a detergent. Photographed in the Boyce Thompson Arboretum, Arizona.
 
left: Agave ocahui var. longifolia (Ocahui, Amolillo) flowering (right) at the Desert Botanic Garden, Phoenix, Arizona, mid-April 2006. The stiff smooth leaves of this less-common variety are up to 3 ft long and 1 in wide and without marginal teeth.

Agave palmeri with a developing flower spike and lanceolate leaves, growing in the Coronado Memorial Monument, Coronado National Forest, Arizona. May 1997. Agave palmeri is distributed in south-eastern Arizona, south-western New Mexico and adjoining states in Mexico at 3000 - 6000 ft above sea level and prefers limestone soils.
 
Uses include production of mescal from the starchy core and fibre from the leaves. The growing bud can be roasted and eaten.

Agave parryi flowering in the Devil Mountains, Organ Pipe National Monument, Arizona. May 1997. Plants may be solitary or clump and three varieties have been described. The pale yellow flowers are carried on a 20ft inflorescence.
 
This plant has been traditionally used for making mescal and is widely used as an ornamental plant for the dry garden.

The neat blue gray rosette of Agave parryi makes a handsome specimen in cultivation. As suggested by its wide distribution through Arizona into New Mexico and northern Mexico at 1500 - 8000 ft above sea level, this species is tolerant of a range of cultural conditions including a substantial degree of cold hardyness. However, it experiences dry cold in habitat and may need some protection from a wet winter, although seen here (left) outside in a protected corner of RHS Wisley during the English winter.

Agave parviflora flowering on a sloping rock face alongside the Ruby Road, Arizona. May 1997. The flowers are pale yellow along a stem 3-6 ft tall. This species has a limited distribution in southern Arizona and northern Sonora, Mexico.
In cultivation, this attractive minature requires full sun and minimal watering to maintain the compact short-leaved form.

Agave pelona is similar to Agave ocahui but its dark green leaves have a reddish tinge towards their tips, a dehiscent white border and a stronger grooved terminal spine up to 3 in long. The rosette is solitary and produces an unusual 10 ft raceme of reddish bell-like flowers.
Agave pelona is native to North-Western Sonora, Mexico and was a source of fibre and roasted Agave hearts for indigenous people. Photographed in the Boyce Thomson Arboretum, Arizona.

Agave polianthiflora has a very similar rosette of leaves to Agave parviflora, with which it is often confused, but has pink flowers. Agave polianthiflora grows on rocks in Northern Mexico at 4000-6000 ft.
The specimen shown here was bought as Agave parviflora but is probably Agave polianthiflora. It is moderately hardy and, potted up in granite chippings to provide free drainage, has survived outside through several English winters under a half plastic bottle as protection from excessive wet. It finally flowered during an indifferent summer and has produced several offsets.

Agave potatorum is one of the choicer small Agaves for the collector and many varieties have been described. This subtropical species grows 4500 - 7500 ft above sea level in Puebla and Oaxaca, Mexico and is not frost hardy.
This specimen was photographed in the Boyce Thomson Arboretum, Arizona. May 1997.

Agave salmiana (Maguey de pulque) is a huge plant, growing over 6ft tall and 12 ft wide. The thick fleshy leaves are guttered. Their margin is undulate with large brown marginal teeth. The inflorescence is a substantial panicle of yellow flowers.
This plant is the species most comonly used to produce pulque in Mexico. It is used as an impressive ornamental in Mediterranean climates. Photographed in the Boyce Thomson Arboretum. Arizona.

Agave schottii (Amoliyo = soap) flowering on a grassy hillside alongside the Ruby Road, Arizona. May 1997. The narrow leaves, with slightly filamentous edges, blend into the grassland making it hard to see except for the current and old inflorescences. The plant contains saponins (soapy substances) and was used to wash clothes. The yellowish flowers on the short inflorescence are noted for their fragrance.

left: Agave schottii
middle: Agave schottii var treleasei
at the Desert Botanic Garden, Phoenix, Arizona September 2004. A collection of several varieties of Agave schottii is planted out here.

Agave tequilana is perhaps the most important Agave for it is from the emerging flower spike of this plant that Tequila is made. It originates from the state of Tequila in Mexico, where selected clones are grown commercially. This species may be seen bedded out as a large specimen plant in warm climates.
 
The bluish leaves have finely toothed margins. The inflorescence of this specimen was taller than the Princess of Wales Conservatory at RBG Kew.

Agave toumeyana ssp. toumeyana at the Desert Botanic Garden, Phoenix, Arizona. This species grows up to 1ft tall in dense clumps at elevations of up to 4500ft in central Arizona. The leaf margins are smooth or with tiny teeth and markedly filmentous. The inflorescence is up to 8ft tall with greenish-yellow flowers.

Agave toumeyana ssp. bella is a selected cultivar of A. toumeyana with brown leaf margins, decorative white leaf markings and particularly curly leaf filaments. Best grown as a single rosette to show off the markings.
Photographed at the Boyce Thompson Arboretum, Arizona.

Agave utahensis (Yant) forms large clumps, with individual rosettes having large numbers of stout bright green leaves up to a foot long and marked with bud imprints. Leaf margins carry small widely spaced gray teeth with a characteristic basal ring. Leaf tips have gray spines with a groove on their upper surface. The inflorescence is up to 8ft tall and variable in form, but generally a panicle of light yellow flowers.
Growing further North in Arizona, California, Nevada and Utah than other Agaves, this plant is extremely cold tolerant, but only if kept absolutely dry when cold. It has been used as a source of fibre for cordage.

Agave victoriae-reginae, named for Queen Victoria I of England, forms a distinctive rosette of stiff thick leaves with distinct "keels" and longitudinal white markings. Rosettes may be a little over 2 ft in diameter and are usually solitary or offsetting sparingly. The inflorescence is a 10 ft spike of white flowers with a reddish tinge.
This plant is prized by collectors, although it is not easy to grow a large unmarked specimen. Several cultivars have been named with different patterns of white leaf markings or no white markings (var. viridis) or variegation. This species is native to Northern Mexico where it is rare. Photographed at the Boyce Thompson Arboretum, Arizona.

Agave vilmoriniana (Octopus Agave, Amole) is a large solitary plant up to 5ft in diameter. The light bluish-green leaves with smooth brown margins have swollen bases and taper to a fine, sharp but flexible terminal spine. The plant produces a 15ft dense raceme of yellow flowers and numerous bulbils.
 
Agave vilmoriniana is native to Northern Mexico, growing between 2000 and 5500 ft, typically growing on the face of cliffs and steep canyons. It is not hardy to more than slight freezing temperatures, but a splendid ornamental plant for Mediterranean climates. The common name "Amole" indicates its use as a source of the soapy saponin (smilagenin) for washing clothes. Photographed at the Boyce Thompson Arboretum, Arizona, May 2006.

left: Agave weberi inflorescence reaching skywards at the Boyce Thompson Arboretum, Arizona, May 2006. This large species up to 5ft tall and 10 ft across has slightly concave, flexible gray-green leaves with fine teeth along their margins to a greater or lesser extent. The terminal spine can be well over an inch long. The flower spike is a panicle up to 26 ft tall, bearing bright yellow flowers and may produce bulbils as well as seed. Offsets are produced freely.
 
Agave weberi is apparently only known from cultivated forms in Mexico and SW USA. It is sometimes used as a source of fibre or pulque. Although a low-desert plant it is frost hardy and can suffer from excessive heat.

Pests of Agaves:

Rabbits and other rodents may eat fleshy leaves or into the starchy core of a plant. These pests can be exclude by wire mesh fencing, which should be partially buried in the ground to discourage burrowing.
 
The main pest is Agave Snout Weevil Scyphophorus acupunctatus, a glossy black beetle-like insect with a pointed snout, typically seen in late Spring and early Summer. The adult insects feed on sap from the leaves and may introduce harmful bacteria. However, the real damage is done by their larvae which infest the starchy core and roots of a mature plant leading to wilting leaves and collapse of the plant. The female weevil lays eggs on the base of lower leaves of a plant that is ready to bloom. The consequences for an Agave monoculture, such as for the production of Tequila, can be devastating. It is unlikely that this particular species of weevil will occur outside the native range of Agaves, but other species of weevil can sometimes be seen feeding on leaves. Although Agave Snout Weevil prefer the broader-leaved Agaves, any genera within the Agavaceae e.g. Beschorneria are at risk.
 
Any snout weevils seen around a plant should be killed and a systemic insecticide applied. Prophylactic treatment of an Agave collection, within the native range of the weevil, with a systemic insecticide may be advisable. Obviously this is impractical if any part of the plant is to be consumed or fermented.
Once a plant has collapsed, it is too late for treatment. The infected plant should be removed and burned, along with grubs that can be found. Watering nearby plants with a systemic inecticide may help to control the pest.