Yuccas, Yeah!

YEARS AGO when I lived in Ravenna, a visiting relative turned a withering eye on my front rockery and pronounced yuccas have no place in Northwest gardens. I was crushed; as a new gardener I was enamored of that big old yucca as the one distinctive element in a juniper- and basket-of-gold-clad rockery. Now I wonder what this rhododendron-loving critic would make of all the spiky shrubs punctuating the coolest gardens around. Have you been on any garden tour lately where the properties weren't peppered with phormiums, cordylines, agave, yuccas and even cacti?

And no wonder these architectural plants are so popular. They've become our new shrubs of choice. Everytime I see a yucca or agave I'm amazed such drama queens flourish here in the land of broadleaf evergreens. Such geographic dislocation is the result of all the new, hardier species and cultivars on the market.

It helps that we've become savvier about understanding that, when planted in free-draining soil and protected from winter wet, these dryland beauties are far hardier than we ever suspected. Also, our winters are warmer than they used to be. Didn't we once garden in Zone 7? What a trick to now be gardening in Zone 8 without moving. Although after seeing Al Gore's movie on global warming, I think the down side of such seeming wizardry is all too clear.

But just because we can grow them, should we? It depends on how they're used. Too many plants with strong vertical lines lend an aggressive, overtly masculine feel to the garden that is neither relaxing nor welcoming. Used more sparingly, their contrasting shapes animate a garden. Sharp blades slicing through fluffy grasses or mounds of perennials create striking silhouettes. And for extra impact, yuccas' theatrical foliage comes in bright stripes, shades of steely blue or ghostly gray, barbed, toothed, erect, splayed or gracefully curved.

Chosen and sited well, yuccas, agaves and phormiums are a minimalist gardener's dream. They're nearly bulletproof, drought tolerant, maintenance-light, and look good year-round. I recently saw a statuesque yucca topping off an elegant urn in the center of an overblown, old-fashioned rose garden. The strong, unchanging lines of the yucca held the whole voluptuous scene together, offering a striking contrast between permanent and ephemeral, rigid and blowsy, soft and sharp.

While the crisply delineated edges of these plants are a big part of their effect, remember their razor-like blades can be dangerous. Yuccas aren't known by such common names as Spanish dagger and Spanish bayonet for nothing. Yucca recurvifolia is a good choice for garden beds because the spines on its leaf tips bend to the touch so you can actually weed and cultivate around it without injury.

How best to care for these plants native to more arid climates? Planting in raised beds or containers helps drainage. Waterlogged soil means death more surely than freezing weather, so add plenty of grit to the soil. Mulching with pebbles or gravel keeps the neck of the plant dry so it doesn't rot. The south side of the house, near a wall or pavement where a yucca can bask in radiated warmth, is an ideal location. A tree canopy or eaves in winter protect yuccas from winter wet, and an insulated wrap, or even a blanket or bath towel during freezing weather, helps them survive an especially cold night.

Sanguine as we've become about our warmer winters, hardiness is still a consideration. Yuccas with single or multiple trunks usually come from the tropics, while stemless, ground-hugging yuccas are a better choice because they're native to cooler habitats. Yucca filamentosa and Yucca flaccida are hardy stemless yuccas. Y. filamentosa 'Bright Edge' is a dwarf cultivar with creamy flowers and yellow-edged foliage Y. flaccida 'Golden Sword' has broad, showy yellow stripes. Also dependably hardy is the exotic-looking Yucca whipplei, with gray-green swords of narrow foliage that grows in tight bursts like a samurai's fan.

Valerie Easton is a Seattle freelance writer and contributing editor for Horticulture magazine. Her e-mail address is valeaston@comcast.net.