In the Garden Articles

The Beauty of Coral Bells and Heucheras

by Joan S. Bolton

Once upon a time, coral bells were sweet, little unassuming shade plants that bore wiry stems of tiny coral, white or reddish-pink flowers above clumps of green, heart-shaped leaves.

But then the hybridizers got hold of them, and coral bells haven't been the same since -- with the leaves of new introductions now appearing with crinkles and ruffles, and in shades of purple, orange, chartreuse and metallic tones, along with vivid red and white veins. Flowering has been ramped up as well, with hybrids bearing literally thousands of dainty white, pink or red flowers along green, red or burgundy stems.

Coral bells have undergone a name change, too. Perhaps because the common name is no longer adequate, an increasing number of gardeners refer to them by their botanic name, Heuchera.

And even that has undergone change. For years, we've pronounced Heuchera as "hew-ker-uh" or "hoo-ker-uh." Now some purists insist on "hoy-ker-uh." That's because the plants were named after an 18th century German professor of medicine, Johann Heinrich von Heucher, and apparently plant names are to be pronounced according to the native language of the person being honored.

But whether you call them coral bells, hew-ker-uhs (like me) or hoy-ker-uhs (way too esoteric), they're one of my favorite shade plants for Central Coast gardens.

Going Native

Heuchera encompasses some 50 species of perennials native to North America.

Lucky for us, three are native to Santa Barbara County, including the long-popular Heuchera maxima, also known as island alum root. It grows wild on hillsides, canyon walls and rocky cliffs on Anacapa, Santa Cruz and Santa Rosa Islands. I've grown it for years beneath a coast live oak (Quercus agrifolia), where it forms ever-broadening, knee-high clumps of medium-green leaves, and sends up sprays of pink-tinged, ivory flowers most heavily in spring and intermittently through the rest of the year.

Maxima is the parent of some stellar hybrids, including Santa Ana Cardinal and Wendy. Both are crosses with Heuchera sanguinea, which is native to Arizona, New Mexico and Mexico. Santa Ana Cardinal grows about 2 feet tall and wide, and pushes up a flurry of 3-foot-tall spikes of bright rose-red flowers from spring through summer. Wendy is a little taller, a little broader and packs more tall stems of pink flowers per inch than any other Heuchera I've seen.

In the 1980s, the late Dara Emery at the Santa Barbara Botanic Garden hybridized a series of smaller species native to mid-level elevations in California with that same Heuchera sanguinea. Emery's little jewels are all low-growing compact, profuse bloomers. Most have "canyon" in their name, such as Canyon Belle, Canyon Delight, Canyon Duet and Canyon Pink.

Western hybrids with maxima and sanguineum as parents offer the best prospects for long lives in our temperate climate, provided they receive filtered light, decent drainage and not too much summer water. Most bear delightful sprays of long-lasting flowers above traditional medium-green leaves.

Farther Afield

If you want to rev up your garden with Heucheras with technicolor leaves, you'll need to cast a wider net.

Palace Purple was one of the first truly purple Heucheras, arriving in the early 1990s. It counts Heuchera micrantha as a parent, which is native to a broad sweep of the northwest, from British Columbia and Idaho to northern and central California, on moist, rocky banks and cliffs.

On its heels have come such standouts as Crimson Curls, Cathedral Windows and Plum Pudding. Many more purples are on the way. Monrovia alone lists four new exclusive Heucheras with at least a tinge of purple for 2008: Caroline, Crystal Spires, Moonlight and Rose Majestic.

Monrovia's four new ones were created by Charles and Martha Oliver. The prolific East Coast hybridizers have been working with eastern species that typically thrive in cold areas with moist, well-drained soil. The Olivers have to keep cold tolerance in mind, since obviously they don't want their new beauties to perish beneath a blanket of snow or in icy winds.

Unfortunately for us, that doesn't necessarily translate to a long-lived plant on the Central Coast, with our warm, dry summers, mild winters and often heavy soils. Give those easterners too much summer water and they may rot. Keeping them dry during summer might not please them, either. Deprive them of cold, cold winters and you'll add to their plight.

This doesn't mean you should avoid Heucheras of eastern parentage. But don't be surprised if they grow like gangbusters for a few years, then decline. That was certainly the case with Crimson Curls in my garden. The plants were spectacular in a lightly shaded planter with relatively loose soil for two or three years, growing 2 feet wide and tall, and bearing luscious, crinkly leaves in beautiful shades of purple and green. Earlier this year they began to fade into sorry clumps of their former selves.

While a weakening in any variety of Heuchera can be due to mealybugs, which suck the nutrients from the leaves, there was nary a downy-looking pest in sight. My husband couldn't stand it any longer and yanked them out.

Of course, with all the new fancy-leaf Heucheras coming out, I'm planning to plant more. The old Crimson Curls complemented a plum-colored Chinese fringe flower (Loropetalum chinense 'Plum Delight'). This time around, I'm thinking of planting Lime Rickey, with chartreuse foliage, or Snow Angel, which bears green leaves splashed with white. Lime Rickey has a cross-country heritage, with bits of micrantha, sanguinea and an eastern species, americana, while Snow Angel is a sanguinea selection.

I'm not too concerned. It's the play of contrasting leaves that will power the show for the next few years. By then, I'll be ready for another round.

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How to Use Heucheras

Heucheras, AKA coral bells, are terrific in the shade. They also do well with morning sun or all-day filtered light. Avoid full sun or late afternoon sun: in those settings, the leaves may scorch. Regardless of the exposure, they're at their best with lighter soil and good drainage, which mimics the native habitats of most species.

The plants are perfect for edging a sheltered, woodsy path. Given their relatively small size, cluster at least three or four together. For greater impact, plant a swath, or mass a dozen or more for a small, informal ground cover.

Fancy-leaf types provide year-round interest with their colorful foliage, while the traditional greens typically bloom in early spring through summer, producing hundreds of tiny flowers up stiff, narrow stems.

For the past 10 or 15 years, Heuchera hybridizers have tended to create plants with either interesting leaves or prolific flowering. More recently, hybridizers have begun combining those traits, working toward creating plants with showy leaves and impressive flowers.

Seeds of Wisdom

Heucheras grow well in containers. You can admire their interesting leaves up close, plus control their sun exposure, soil and irrigation. Provide perfect drainage by using loose, fertile potting soil. Let the top inch dry out between waterings.