Coral bells (Heuchera), foam flowers (Heucherella) and foamy bells (Tiarella) are three closely related genera. While they are frequently selected as a pleasant choice for the front of a shade border or a nice accent in a tapestry of low-growing, woodland inhabitants, hybridizers over the past decade have made great strides in creating far more versatile plants. These three plants now offer an enormous diversity of colorful foliage and delicate flowers for all sun conditions in the garden. And deer tend to place coral bell, foam flowers and foamy bells fairly low on their menu, which adds to their appeal.
One objective of recent hybridizing programs has been a search for the coral bell with the darkest foliage. The result has been a number of newer cultivars that range from chocolate brown to deep burgundy brown, with the ultimate goal of producing a Huechera with true-black foliage. These dark-leaved cultivars are best suited to partly shaded to shady sites and are relatively easy to acquire.
Heuchera ‘Black Out’ is one of the blackest coral bells on the market. It has glossy, deep, burgundy foliage that transitions into black with burgundy overtones on its undersides. ‘Black Out’s maple-shaped foliage is medium sized and has a compact shape (without being too small) that makes it ideal for container plantings. This plant can stand up to the New York area climate, though some die back and loss of vigor may occur following a particularly harsh winter.
Another winner for the New York area is Heuchera ‘Frosted Violet Dream’. This coral bell has deep burgundy foliage that is mottled with silver. The maple-shaped foliage shimmers in a garden setting. It is another medium sized coral bell that is a vigorous grower with a spectacular performance record. In early to mid summer this coral bell is covered with an attractive haze of dainty pink flowers.
Coral Bells have been bred for other, pleasing, flower and leaf characteristics. Oregon-based Terra Nova Nursery has come out with a ‘Soda Series’ of coral bells that include cultivars named ‘Root Beer’, ‘Ginger Ale’ and ‘Cherry Cola’. ‘Cherry Cola’ is a compact plant with rounded leaves that morph between red and chocolate brown. It grows to be about 6 inches tall and 14 inches wide making it well suited for a container or the front of a border. But what really distinguishes Heuchera ‘Cherry Cola’ from other colorful coral bells is its flower. In the spring it produces a rich display of cherry red flowers that cover the plant and create quite a sensation. It is also fairly winter hardy and happiest in part shade but can handle sun and shade.
Heuchera ‘Ginger Peach’ is a vigorous coral bell that grows 10 inches tall and 24 inches wide. Its maple-shaped leaves are ruffled with a rose colored backside. The leaves change from copper to peachy coral. This coral bell is hardy from zone 4 to 9 and is more admired for the foliage than the flower.
Though coral bells were traditionally thought of as shade lovers, there are also spectacular options for sunny sites. Heuchera villosa is a species that is native to the southeastern U.S., that thrives in full sun to part shade, grows happily in soils ranging from slightly wet to slightly dry and is unfazed by high humidity. Hybridizers have latched on to this species and it is now part of the parentage of many successful hybrids.
The French hybridizer, Thierry Delabroye has taken the world of coral bells by storm, flooding the market with a number of mouthwatering cultivars that include ‘Carmel’, ‘Brownies’, ‘Mocha’, ‘Pistache’, ‘Tiramisu’, ‘Pinot Gris’ and ‘Beaujolais’.
The reputation of Heuchera ‘Brownies’ as an attractive and adaptable coral bell is attested to by the fact that it is flourishing in the challenging environment of New York’s High Line park. Its foliage emerges brown and then transforms into a greenish brown with a rich purple-red underside. Like the majority of Heuchera villosa hybrids, it features large foliage and has a fuzzy texture. It grows over a foot tall and forms a generous two foot clump.
The American hybridizer, Dan Heims, has a selection of Heuchera villosa hybrids that are also worth searching out. The names of his cultivars hark back to the species’ regional heritage with cultivars such as ‘Southern Comfort’ and ‘Georgia Peach’.
Heuchera ‘Southern Comfort’ starts the season with peachy, amber tones that morph into a coral color by autumn. This cultivar over-winters beautifully and explodes with a kaleidoscope of colors in the spring. It is also a large specimen reaching 15 inches tall with a spread of over two feet.
When you are growing these coral bells in sunny environments make sure that you are conscientious with your watering practices while they are getting established. After they are settled, remember to water them during extended dry spells. They will protest when subjected to excessive heat and drought by browning on the leaves.
Do not pamper these coral bells by feeding them heavily with fertilizer. They are vigorous to start with and you will just encourage excessive growth that will collapse under challenging circumstances. Allow them “tough it out.”
Foam flowers have a limited palette of flower color; they have attractive, foamy white to pale pink flowers in early spring. One admirable cultivar is Tiarella ‘Sunset Ridge’. ‘Sunset Ridge’ has a wonderful trailing habit and is a vigorous grower, making it a fine ivy substitute for your garden or a hanging basket. The leaves on ‘Sunset Ridge’ have deep, large, burgundy markings highlighting its veins and, like its brethren, it has foamy white flowers.
When you take a coral bell (Heuchera) and cross it with a foam flower (Tiarella) what do you get? Foamy bells (Heucherella), of course! Foamy bells are an intergeneric hybrid, meaning that they are a hybrid of two closely related genera. As an intermediate form, foamy bells have the characteristics of both parents and are sterile, which means they need to be propagated vegetatively.
Foam flowers and foamy bells perform best and have the most vivid leaf colors when grown in afternoon shade. Some of the newer cultivars can handle quite a bit more sun and grow more slowly when grown in deeper shade. Tiarella ‘Solar Power’ has lime green and red leaves and ‘Gunsmoke’ has smoky purple and silver foliage. Both of these cultivars can be grown in sun or shade.
The hybridizer Dan Heims, of Terra Nova Nurseries, has also put his hand to hybridizing foamy bells (Heucherella) in a wide variety of colors and sizes. One of Terra Nova’s notable foamy bells is ‘Honey Rose’. This is one of the pinkest leaved foamy bells on the market. The young leaves are coral-pink with deep venation that changes to a deep, apricot brown. ‘Infinity’ is known for its long flowering. This Heucherella has velvety, chocolate-colored foliage along with cream-colored flowers held up on 2-foot spikes that bloom continuously from May to September.
There are so many new cultivars on the market these days and some may be more vigorous than others in your region. It is always a good idea to try a few of these plants in your own garden, judging for yourself what is going to work for your unique climate before making a large investment in these delightful foliage plants.
Many of these perennials can be semi-evergreen in the New York City-area. Generally you can wait until spring (April) before cleaning up any ratty foliage on these plants. Once you see that these plants are pushing new growth, follow the stems back to the crown of the plant and remove that ratty foliage. Make sure not to cut into the crown of the plant (the base of the plant where the growth comes from). You generally don’t have to clean up foam flowers, but coral bells and foamy bells will often require this spring time grooming. Coral bells and foamy bells are sometimes at the mercy of frost heaves during the winter months and can benefit from a layer of mulch once the ground freezes over.
Heucheras and Heucherellas by 
Rodale's Illustrated Encyclopedia of Perennials by 
The American Woodland Garden by 
Planting the Dry Shade Garden by 
