The hubbub over heucheras

For Marsha Stout, heucheras are a passion. She has grown many, lost many. She trolls nurseries, plant sales and garden shows for more.

“I’m not a designer,” she says of her eclectic plant-plump garden in Santa Monica. “I’m a collector.”

Stout isn’t alone in her love of heucheras, pronounced HOY-ker-ahs, HUE-ker-ahs or WHO-ker-ahs, depending on one’s horticultural tongue. These tidy perennials -- also known as alum root or coral bells -- are about as hot as any garden plant can be. Demand keeps growing, nurseries say, along with availability and the number of new varieties.

Why the hubbub? Heucheras are easy, forgiving and long-lived in the ground or in pots. They thrive in dry shade and other difficult spots with minimal care. And they’re simply gorgeous -- in and out of flower, on their own or mixed with other plants.

Long ago in garden centers, only a smattering of heucheras could be found -- usually hybrids of H. sanguinea, the coral bells of the Southwest and Mexico, with mottled green leaves and sprays of rosy pink blossoms. A number of extremely floriferous heucheras with California heritage were rarely grown or sold outside native plant circles.

Tastes changed following the 1980 unveiling of Heuchera ‘Palace Purple,’ a sensational variety from the Royal Botanic Gardens, Kew, with ruffled leaves as dark and glossy as a just-picked eggplant. Gardeners went bonkers for coral bells. Plant breeders and propagators smelled a trend and got to work.

These days a remarkable range of heucheras and the related hybrid, heucherella, can be found in 4-inch or 1-gallon nursery containers: early-blooming island alum root from the Channel Islands (H. maxima); classic drought- and heat-tolerant hybrids from California sources; and scores with foliage in otherworldly hues, the majority from Dan Heims of Terra Nova Nurseries near Portland, Ore. (www.terranovanurseries.com).

Heims, a self-declared “hortiholic,” is coauthor of “Heucheras and Heucherellas: Coral Bells and Foamy Bells,” written with Grahame Ware and released three weeks ago by Timber Press. His breeding program, led by Janet Egger, has produced scores of unusual heucheras.

The plant’s rounded or heart-shaped leaves may be dull and glossy, with scalloped or ruffled edges. The tiny bell-shaped flowers, no larger than peas, appeal to hummingbirds and hang in open clusters on wiry stems that shimmy in the breeze, releasing puffs of grainy pollen to foraging syrphid flies.

Because new fancy-leafed hybrids owe their size, texture, metallic markings and magical hues to the alum root of eastern woodlands (H. americana), they don’t always flower or persist in this climate -- at least not as well as heucheras with western bloodlines, most of which are crevice-dwellers more adapted to a rugged life.

“Western types are noted for their longevity,” says Bart O’Brien, director of horticulture at Rancho Santa Ana Botanic Garden in Claremont. One planting there of pink-flowering ‘Wendy’ dates to the mid-1980s. A display of many Western species and most cultivars at the Santa Barbara Botanic Garden includes clumps of ‘Canyon Delight’ in the ground since 1988.

“They really do their best under deciduous trees, especially deep-rooted native oaks and sycamores,” O’Brien says. “Full sun through the winter is fine and makes them bloom well, but they need shade during the summer, especially this far inland.”

The challenge, says Carol Bornstein, Santa Barbara Botanic Garden’s director of living collections and nursery, is that leaf duff from overhanging trees can bury the smaller heucheras. Though all types are relatively compact -- the tallest mound to 2 feet or so with 30-inch flower spikes -- some are smaller than others.

“The tiny ones are great pot plants,” O’Brien says. The smallest of them all, H. parishii ‘Chiquita,’ can stay in a 4-inch pot for what seems like forever. Its leaves are about the size of a pencil eraser, and the dainty flowers are pinkish white on 3-inch high spikes.

H. elegans ‘Bella Blanca’ is a white-flowered mat-forming albino collected by O’Brien in the San Gabriel Mountains. “Great for rock gardens,” he says.

Dan Heims says “heuchs” (rhymes with cukes) are the best container plants in the world. “They play well with others,” he says. They don’t compete and don’t mind drying out. A lot of their kin, he adds, live in cracks in rocks where they bake in the sun, “and when rains come, they bloom their heads off.”

David Fross, president and owner of Native Sons wholesale nursery in Arroyo Grande (www.nativeson.com) and a horticulture lecturer at Cal Poly San Luis Obispo, grows western and eastern types in his garden. His most precious: a 17-year-old clump of ‘Canyon Pink,’ a gift from its creator, the late Santa Barbara Botanic Garden horticulturist Dara Emery.

“Heucheras, in general, fill a glaring need in urban and suburban gardens,” Fross says. “They work in half-light or with only two hours of hot sun in a narrow corridor or between buildings.”

Fross says some eastern heucheras look bad in hot weather but bounce back. “They establish their own natural rhythm but last only two to three years, if I’m lucky,” he says. His wife planted Terra Nova’s award-winning hybrid ‘Amber Waves’ in a red clay pot, and “it’s doing really well.”

Fross and other gardeners have noticed that salmon-, peach- and apricot-colored hybrids can take more sun, even in Southern California. Heims cites three of his latest -- ‘Peachy Keen,’ ‘Peach Flambe’ and ‘Peach Melba’ -- for their heat-tolerance. “The beauty of hybrids,” he says, “is that they incorporate the genetic benefits of different species.”

Ruffled heucheras such as ‘Marmalade,’ which has large undulating leaves that vary from umber to deep sienna, often do well in Southern California, Heims says, thanks to genes from a western species, H. micrantha.

One clump of such plants is lovely, but heucheras en masse are spectacular. Rick Fisher, principal of Toyon Design, Landscape Architecture, used three showy western hybrids -- a white, ‘Opal,’ and two pinks, ‘Wendy’ and ‘Old La Rochette’ -- in large groups at the base of a eucalyptus windbreak at the Sam and Alfreda Maloof Foundation for Arts and Crafts in Alta Loma.

“I’d grown one or two before,” says Beverly Maloof, a home gardener and wife of artist and woodworker Sam Maloof. “But I’d never seen them in big wavy beds and seen the effect from a distance. The wands all move together.”

The Maloofs’ heucheras began flowering at the end of March. ‘Opal’ and ‘Wendy’ showed color into May then faded with the heat. (‘Opal’ has lived and flowered more generously than any other heuchera in Santa Monica gardener Stout’s collection.)

The plants need water every two weeks during the warm months and none in winter, and they’re never fed.

“Too much nitrogen is a good way to kill heuchs,” Heims says.

Pests are rarely deadly. When rust (a fungus) and insects (mainly mealybugs) attack his heucheras, Fross “rejuvenates” his plants with a string trimmer. They sprout again quickly.

Bornstein reports “serious predation” of foliage in the Santa Barbara Botanic Garden’s nursery by mice, rats and chipmunks. “They leave nothing but ragged leaf stems,” she says. But most problems, O’Brien says, stem from too much water in summer.

As if their stamina wasn’t enough, coral bells -- the flower spikes and the leaves -- are great for cutting. Heims says a leaf cut from one of his hybrids survived in a vase for two years. H. micrantha ‘Martha Roderick’ is a favorite of Bornstein’s.

“It’s the number of flowers and how they’re held on the stalks -- very airy with millions of small flowers,” she says. “It’s absolutely gorgeous.”