In the Garden: Beauty of the desert blooms on
Although most people know the yucca as a large house plant with sword-shaped, spiky leaves, there are also some spectacular outdoor forms that are easily grown. Indeed, because the indoor yucca grows so big, some specimens found themselves moved to the garden, where they grew well until they were wiped out in a cold winter.
Yucca forms a rosette of spiky leaves that contrasts wonderfully with the rounded shapes of most shrubs and flowers. It looks especially well with gravel or paving and a single plant can liven up a garden or part of a large garden. But it also flowers in most spectacular fashion with a towering column of ivory-white flowers.
The flowers are carried on a single stem arising from the rosette or head of leaves. Hundreds of wax-like dangling bells are produced. The flower stems last well over several weeks between late summer and late autumn. Old plants with more than one rosette of leaves might produce several flower stems.
Yucca species come from the southern arid states of the US and Mexico. They are plants of near-desert conditions, armed with the sharp spines to deter grazing by animals. Their natural habitat of dry, rocky places explains why the plant looks so well with rock or gravel.
The most widely grown and available is Yucca filamentosa, or Adam's needle. It forms a clump of spiky rosettes because it makes very little stem growth. It's a neat grower compared to other species which tend to have stems that flop to ground after a few years. It has a good spike of flowers produced in mid to late summer. It often takes two or more years to flower after planting because the plant needs to make enough size to produce such large flowers. This species is reliable and will flower in most years, and perhaps every year.
The other widely-grown kind, Yucca gloriosa, called Spanish dagger, is bigger with a more robust stem that branches to make several rosettes. It can stay more or less upright, but often leans over, even to soil level. It makes a very large flower, to over 2m tall, with waxy white flowers that may be purple-tinged. It blooms later than the Adam's needle, flowering from late-summer into autumn.
All yuccas need to be grown on dry, free-draining soil. A gravelly soil with humus dug in to get them started is ideal, in full sunshine and good air movement. Snails can lodge amid the leaves and feed on the flower stems as they emerge, causing severe distortion and damage to the flower spikes.