Yucca kanabensis McKelvey and Yucca toftiae S.L.Welsh are sometimes treated as distinct. However, there is significant intergradation among these taxa, which makes their recognition at varietal rank seem most appropriate[
Yucca kanabensis McKelvey
Yucca toftiae S.L.Welsh
Yucca angustissima is an evergreen shrub producing a rosette of spear-shaped leaves 20 - 80cm long (exceptionally to 150cm) and 4 - 20mm wide growing from a procumbent stem 10 - 40cm long or, less commonly, from an erect stem 100 - 200cm long. The plant can produce a solitary rosette, or can form small to large colonies of rosettes[
The plant is harvested from the wild for local use as a food and source of materials. The roots of Yucca species are rich in saponins and have a wide range of applications. The plant is grown as an ornamental in gardens.
The roots contain saponins[
Although poisonous, saponins also have a range of medicinal applications and many saponin-rich plants are used in herbalism (particularly as emetics, expectorants and febrifuges) or as sources of raw materials for the pharmaceutical industry. Saponins are also found in a number of common foods, such as many beans.
Saponins have a quite bitter flavour and are in general poorly absorbed by the human body, so most pass through without harm. They can be removed by carefully leaching in running water. Thorough cooking, and perhaps changing the cooking water once, will also normally remove most of them. However, it is not advisable to eat large quantities of raw foods that contain saponins.
Saponins are much more toxic to many cold-blooded creatures, such as fish, and hunting tribes have traditionally put large quantities of them in streams, lakes etc in order to stupefy or kill the fish and make them easy to catch[
South-western N. America - Utah, Arizona, New Mexico.
Sandy places, sandstone outcrops, rocky hillsides of deserts at elevations of 900 - 2200 metres in Arizona, New Mexico and Utah[
Yucca angustissima is a plant of semi-arid regions of southwestern N. America. It can tolerate temperatures down to about -10°c if in a suitable location, but is very intolerant of winter wet[
Thrives in any soil but prefers a sandy loam and full exposure to the south[
]. Plants can succeed in light shade[
]. They are hardier when grown on poor sandy soils[
]. Established plants are very drought resistant, this species is also tolerant of damp weather[
Closely allied to Yucca glauca[
The plant has a thick prostrate rootstock[
Yuccas are pollinated by small, white Yucca moths (Tegeticula yucasella and related species) with which they have a special plant-insect mutualism. At night, the fragrant flowers attract the female moth that feeds on the nectar. She then rolls pollen from the flowers into a ball that is three times the size of her head and carries the pollen ball to the next flower. There, she first lays eggs inside the immature ovary and then deposits the pollen on the flower’s stigma ensuring that seeds will form to feed her progeny. Because the larvae mature before they are able to consume all of
the seeds (60 to 80% of the seeds remain viable), the plants are able to reproduce as well[
]. In regions where the moth cannot live and, if fruit and seed are required, then hand pollination is necessary[
]. This can be quite easily and successfully done using something like a small paint brush.
Individual crowns are monocarpic, dying after flowering[
]. However, the crown will usually produce a number of sideshoots before it dies and these will grow on to flower in later years[
Plants in this genus are notably resistant to honey fungus[
Members of this genus seem to be immune to the predations of rabbits[
Fruit - the immature fruit is cooked[
]. Baked in an oven[
]. A bitter taste, the bitterness is in the skin[
]. The fruit is 35 - 75mm long and 20 - 30mm wide[
Flowers - raw or cooked. They are delicious raw, or can be dried, crushed and used as a flavouring[
Flowering stem - peeled, cooked and used like asparagus. The whitish inner portion is used[
The roots are antiinflammatory, antitumor, antiviral[
The roots of Yucca species are rich in saponins and medicinally active compounds. The roots, harvested when the plant is not in flower, are used to make a health-promoting drink. It has been shown to lower cholesterol and triglyceride levels in the blood, to lower blood pressure and to reduce symptoms of osteoarthritis such as pain, swelling and stiffness. Yucca schidigera seems to be the species most often quoted, though all species contain the saponins[
Taken orally, the root is used in the treatment of osteoarthritis, hypertension, migraine headaches, colitis, stomach disorders, hypercholesterolemia, diabetes, poor circulation, and liver and gallbladder disorders[
Applied topically, it is used to treat sores, skin diseases, inflammation, bleeding, sprains, broken limbs, joint pain, baldness, and dandruff[
Many compounds from yucca have been used in the synthesis of new drugs[
A fibre obtained from the leaves is used for making ropes, baskets and mats[
The leaves are very fibrous and can be used as paint brushes[
] or as a broom or woven to make mats etc[
]. They are also used in basketry[
The roots are rich in saponins and can be used as a soap substitute[
The juice of the plant has a wide variety of uses. In agriculture it is used as a base in liquid fertilizers where its ability to reduce surface tension of irrigation water greatly assists penetration in heavy soils; it assists in soil flocculation to a marked degree; it serves as a carrying agent for the plant-food chemicals[
]. The yucca extract itself is rich in the vital minor elements including boron, iron, magnesium, manganese, copper and zinc[
The juice is said to be widely used as a carbon dioxide stabilizer in the control of oil fires, and saponin from yucca is considered a good base for soaps, shampoos, cleansing powders, and tooth pastes and powders[
Seed - sow spring in a greenhouse. Pre-soaking the seed for 24 hours in warm water may reduce the germination time. It usually germinates within 1 - 12 months if kept at a temperature of 20°c. Prick out the seedlings into individual pots when they are large enough to handle and grow them on in the greenhouse or cold frame for at least their first two winters. Plant them out into their permanent positions in early summer and consider giving them some winter protection for at least their first winter outdoors - a simple pane of glass is usually sufficient[
]. Seed is not produced in Britain unless the flowers are hand pollinated.
Root cuttings in late winter or early spring. Lift in mid spring and remove small buds from base of stem and rhizomes. Dip in dry wood ashes to stop any bleeding and plant in a sandy soil in pots in a greenhouse until established[