McCreary: Plant yuccas for distinction and dry summers

Although the yucca is native to diverse areas of the Americas, we tend to associate it with deserts and sterile landscapes. But that isn’t really fair to this very interesting genus of plants, though it is likely the reason why yuccas have never been widely planted in Northern California.

It may be surprising, but at least six species are native to the Southeast — along the Gulf Coast, in areas of the Appalachians, and as far north as New Jersey. These also thrive in drier climates such as ours.

The Joshua tree (Y. brevifolia) and our lord’s candle (Y. whipplei) are fairly well known California natives, but are more appreciated in their native habitats than in gardens. The Joshua tree ranges over low and high deserts of Southern California, grows slowly, and has shorter leaves than most yuccas, but they end in dagger-like tips, and mature plants spread 30 feet in both height and width.

Yucca whipplei isn’t much friendlier, though the tuft of stiff, narrow foliage is only about 3 feet high. Leaf margins are lined with teeth and sharp needles form at tips. After flowering the plant dies, but small offsets and seeds are left behind. It is far easier to admire along desert highways than in gardens.

While most yucca foliage terminates in sharp tips, some species are not as pointed; nonetheless, plants should be positioned away from foot traffic or sharp leaf ends clipped off, the only maintenance ever required.

Yucca species vary considerably but generally bear stiff, sword-shaped leaves in a spiky rosette, sometimes narrow along their entire length, sprouting around the base and rising in a sphere or hemisphere; other times, broad at the base before tapering to a narrow point. All develop striking architectural poses.

This sculptural quality, the wonderful hues — deep green, golden yellow striping, bluish grays, red or white margins — and drought tolerance all make yuccas good candidates for our gardens.

Even though many are native to desert regions, they are quite versatile in the landscape and combine easily with non-desert species. Their showy cream colored, bell-shaped flowers are borne in large clusters on stalks usually rising above the foliage, often on multiple stalks with staggered bloom periods. They never fail to win acclaim.

Yuccas are often singled out for focal points in gardens to stand alone or with boulders and gravel mulch. But thick, leathery leaves also blend easily with tropical foliage, are effective in contrast with grasses, and can be perfect partners for wispy, low-growing flowering plants that ramble over the ground in sunny sites.

Small stars

For gardeners who favor small plants, there are several yuccas less than 3 feet in height. When making a purchase, always check for mature size since some very winsome species stay small for several years, but eventually take off and become 6 or 10 feet tall. The following are suitable for any garden.

Banana yucca (Y. baccata) named for the shape of its edible fruit pods grows slowly to 3 or 4 feet. Stiff, sword-shaped leaves branch from the ground and may be bluish or yellow-green with thin, curled filaments along margins.

New Mexico yucca (Y. harrimaniae) is similar but often smaller and more compact with narrower grayish to bluish green leaves.

Twisted leaf yucca (Y. rupicola) is smaller still at 18 x 18 inches and is considered more handsome for its wider leaves that twist and undulate. Foliage varies from bright to dark green.

Pale yucca (Y. pallida), quite stunning and also 18 x 18 inches, has 2-inch wide silver-blue leaves. As plants age, lower leaves drape over the ground subtending a cluster of more vertical foliage.

Adam’s needle (Y. filamentosa), one of the most beautiful and widely planted yuccas hailing from the Southeast, varies from an upright clump to a rounded sphere of bluish green leaves broad at the base and tapering to a point. Bright Edge and Color Guard cultivars bear yellow and cream striping. Frizzy filaments peel off leaf margins.

Yucca flaccida, also from the Southeast, is another widely planted species, especially its cultivars Garland’s Gold and Golden Sword whose 1- to 2-inch wide leaves are golden yellow in the center with dark green margins. Lower leaves become quite lax and curve downward while the center cluster is more upright. Several rosettes may form a small colony.

Care and sources

All yuccas prefer sunny sites and fast-draining soil, although the species Y. pallida and Y. rupicola are said to tolerate shade as well as heavy, moist soil.

If your local nursery does not stock these plants, ask for a special order or find a nursery willing to locate the plants for you. Emerisa Nursery in Santa Rosa stocks several; mail order nurseries such as www.soonerplantfarm.com, www.lazyssfarm.com, and www.plantdelights.com carry a number of species and cultivars.

Rosemary McCreary, a Sonoma County gardener, gardening teacher and author, writes the weekly Homegrown column for The Press Democrat. Write to her at P.O. Box 910, Santa Rosa, 95402; or send fax to 664-9476.