Curve Leaf Yucca

Curve leaf yucca resembles other yuccas.

Several of the fifty or so species of Yucca are difficult to distinguish from similar species. Some are varieties of species, rather than distinct species. Some are naturally occurring hybrids. Curve leaf yucca, Yucca recurvifolia, is supposedly a naturally occurring variety of mound lily, Yucca gloriosa var. recurvifolia (or tristis). Alternatively, it could be a hybrid.

As if that is not confusing enough, its physical characteristics are variable. Foliar color is typically grayish, but might be simple olive drab like that of many other species of Yucca. Its typically pliable evergreen leaves that curve downward as they mature can be almost as rigid as those of common mound lily. Stout but upright trunks may or may not develop.

Curve leaf yucca is remarkably resilient. Actually, unwanted specimens can be difficult to eradicate. Small bits of rhizome can generate pups for many years after the removal of a primary plant. Occasional watering is appreciated through the warmest summer weather, but may not be necessary. Old colonies can get ten feet tall, and occupy significant area, but quite slowly.

Mound Lily

Mound lily cultivars are generally variegated.

A few of the fifty or so species of Yucca go by the names of Spanish bayonet or Spanish dagger. Both common names apply to Yucca gloriosa. However, only this single species is also the mound lily. Most other Spanish bayonet and Spanish dagger are from deserts or chaparrals. Mound lily is from southeastern North America, so likes periodic watering.

If that is not confusing enough, the curved leaf yucca, which had been Yucca recurvifolia, is now Yucca gloriosa var.(iety) tristis. It has distinctly pliable leaves with a matte surface texture, and is rarely variegated. Mound lily has stiffer and smoother leaves that are more likely to be variegated. It had been rare, but is becoming one of the more popular yuccas. 

Although it does not grow fast, and takes many years to form stout trunks, mound lily can eventually get taller than six feet. Taller floral panicles rise above the densely evergreen foliage. The small and pendulous flowers are pale white, perhaps blushed with brownish purple and pink. The leaves are about a foot or two long and maybe three inches wide, with very sharp terminal spines.

Giant Yucca

Common giant yucca is uncommonly bold.

Like so many of the plants that became too trendy at one time or another, giant yucca, Yucca elephantipes, had gotten a bad reputation. Some people still consider it to be cheap and common. The real problem though, is that some of the countless giant yuccas planted over the years went into situations that can not accommodate their massively distended trunks. Only a few of the largest specimens are taller than a two story house, and not many get broader than tall. However, their several sculptural trunks are remarkably bulky and flared at the ground.

The somewhat rigid and narrowly pointed leaves can get as long as three feet, and as wide as three inches. Foliage is typically slightly yellowish green, or richer green and a bit floppier in partial shade. Spikes of white flowers that bloom in spring are tall enough to stand just above the foliage, but are usually too high up to be too flashy. Individual flowers are actually only about an inch and a half wide. The bold form and texture of giant yucca work will with other bold plants like giant philodendron, various agaves and various cacti. Shoots and stems of any size that need to be pruned away can be stripped of lower leaves and ‘planted’ wherever new plants are wanted. They only need to be watered regularly until they develop roots like really big cuttings.

Curve Leaf Yucca

Curve leaf yucca can be variegated.

Some perennials are too easy to grow. Curve leaf yucca, Yucca recurvifolia (or Yucca gloriosa ‘Tristis’), is remarkably resilient. It migrates slowly but surely. If it becomes obtrusive, it is difficult to contain and remove. Removal of foliar rosettes above does nothing to slow the roots below. The roots merely produce new foliage. Of course that can be a distinct advantage for harsh conditions.

The striking foliar form resembles that of other species of Yucca, except that it reliably arches softly downward. Foliage is not as soft as it seems though. Each leaf terminates with a sharp spine. Sharp edges can cause wicked paper cuts. Foliar color is bluish gray. Although, variegated cultivars are increasingly popular. Old plants can develop trunks that slowly grow more than six feet tall.

Tall and elegant spikes of relatively small creamy white flowers stand grandly above the evergreen foliage in late spring or summer. Bloom is best with warm and sunny exposure, and lasts a long time. Viable seed is rare. Propagation by division of some of the many pups is simple though. Popular variegated cultivars exhibit more docile growth with fewer pups, but bloom less abundantly.

Spanish Bayonet

P71110From a simple picture, Spanish bayonet, Yucca aloifolia, is indistinguishable from the common giant yucca. The narrow leaves are about two feet long, and flare upward and outward from terminal buds. Plump conical trusses of waxy white flowers with purplish highlights stand vertically just above the foliage. The main difference is that the leaves are more rigid than they appear to be, with nastily sharp terminal spines.

The second most obvious difference becomes apparent as the trunks mature. These trunks get only about four inches wide, which is not quite stout enough to support their own weight. Some might get taller than ten feet, but eventually fall over. Terminal buds of fallen trunks curve upward, and try to grow vertically again. If not pruned away, old foliage browns and lays back against the trunks, like the beards of fan palms.

Yuccas (reblogged)


P71022+Yuccas are almost as useful as aloes are for gardening in chaparral or desert climates. I say ‘almost’ because most are not quite as friendly. The leaves are outfitted with nastily sharp tips. It is how they protect themselves from grazing animals in the wild, but it is not such an advantage in home gardens. Some actually have the potential to be dangerous where someone could bump into them. The leaves of Joshua tree can puncture leather. Some types of yucca get so big that they make it difficult to avoid their nasty leaves, even if planted in the background.

That being said, for those of us who do not need to worry about endangering children, dogs or anyone else out in our gardens, yuccas are very distinctive and handsome plants. Their striking foliage radiates outward from dense foliar rosettes. Large spikes of creamy white flowers that bloom in summer or autumn stand above the foliage quite boldly. Some yuccas produce remarkably tall floral spikes. Our Lord’s Candle, Yucca whipplei (Hesperoyucca whipplei), is a terrestrial yucca that sits low to the ground, but produces a huge flower stalk that stands ten feet tall! Modern garden varieties of Adam’s needle, Yucca filamentosa, are variegated.

Of the yuccas that develop sculptural trunks, only a few are available in nurseries. The giant yucca, Yucca elephantipes, is almost too common in mild climates, and unfortunately develops a massively distended trunk that is too big for some of the situations it gets into. Most other trunk forming yuccas that grow slower are uncommon because they are susceptible to rot in landscapes where they get watered through summer.

Except for a few tropical yuccas that are very rare, yuccas are very drought tolerant. Even in desert climates, some yuccas survive on annual rainfall. Others are happier if watered a few times through summer. Giant yucca happens to be a tropical yucca, but surprisingly does not need much water.

Giant yucca is very easy to propagate from cuttings of the big canes. Even big pieces can be cut and stuck as cuttings. However, most of the tree yuccas are difficult to propagate.

Terrestrial yuccas that do not develop trunks are generally easy to propagate by division of pups, although some are difficult to handle. Some terrestrial yuccas actually develop small trunks that creep along the ground, or maybe stand a few feet tall. They can be propagated as cuttings like giant yucca.