Categories of Coral Bells: The Garden Group
When Coral Bells breeders begin a plant breeding program, they often have an end-goal in mind of the types of plants that they want to create for the commercial market. Breeders identify the important ornamental traits and create breeding programs that focus on improving the important traits over multiple generations of controlled crosses. In this way, breeders make stepwise or incremental advances towards their goals. Occasionally, a sport or mutation will occur in a breeding program that makes a large leap towards a goal or generates a novel trait. In any case, it is important to understand the types of traits that Heuchera breeders are looking for. In their book, Heuchera, Tiarella, and Heucherella: A gardener’s guide, expert breeders Charles and Martha Oliver define 5 groups for Heuchera. For this article series, I am going to use the same 5 groups suggested by the Olivers with some minor name changes and I am going to add ‘cut flowers’ also. Our 6 Heuchera groups are:
1) Garden Heuchera 2) Alpine Garden Heuchera 3) Rock Garden Heuchera 4) Naturalizing Heuchera 5) Collector’s Item Heuchera 6) Cut flower Heuchera
The garden Heuchera (1) are the best for perennial beds and are the main focus of this essay. A large list of garden Heuchera is provided in the ‘Species, Groups and Cultivar List’ below. Most of the garden Heuchera are hybrids with a complex background that includes parents from Heuchera alba, Heuchera americana, Heuchera brizoides, Heuchera cylindrica, Heuchera maxima, Heuchera micrantha, Heuchera pilosissima, Heuchera pubescens, Heuchera sanguinea and Heuchera villosa.
A a general rule, the garden Heuchera are selected to perform well in a garden environment, to have a pleasing mounded habit, to have colorful flowers, and to have a flower stalk that is in proportion to the plant (not too tall, not too short). Breeders then make selections for one or more specific ornamental traits that have commercial value. The most important trait for garden Heuchera is leaf color and leaf color pattern. In the wild, Heuchfera leaves are usually emerald green with the occasional purple vein, bronze/purple tint, or silver interveinal marking. Modern breeders have made extraordinary breakthroughs with leaf color. They have introduced: striking white, silver or purple patterns on the leaf face; bold purple veination; red, bronze, purple, chartreuse or yellow leaf color; and crinkled or wavy leaves. In addition, breeders have improved the flowers by increasing their size, improving the color and altering the bloom time.
Not every Heuchera will grow well in the hot and humid southern U.S. Some breeders are working on creating heat-tolerant Heuchera that are also colorful. Here at Plant Delights Nursery and Juniper Level Botanic Gardens in Raleigh, N.C., we select the most heat tolerant of the available cultivars for our garden and our mail order catalog.
The garden Heuchera can be further divided into categories based on their primary trait of interest.
Group 1: Garden Heuchera divisions: 1a) floral interest, 1b) green foliage 1c) purple or black foliage 1d) red or bronze foliage 1e) chartreuse or yellow foliage
Garden Heuchera with floral interest (1a) generally have bright clear colors, bell-shaped blooms, and a larger flower than the wild types. Modern flower colors include white, pink, coral, scarlet, crimson, and red. Huecheras are grown for their open, airy floral effect in the garden. The flowers look best when grown in large sweeps of 10 or more plants.
Garden Heuchera with green and silver/white foliage (1b) have interesting veination or other pattterned markings on the leaf face. Silver or white interveinal patterns are quite striking, brighten up a shady corner, and bring a formal look to the garden.
Our favorite floral (1a) Heuchera and silver-leaved Heuchera (1b) here at Plant Delights Nursery and Juniper Level Botanic Garden is Heuchera ‘Paris’ with its coral flowers, strong green veins and silver-white inter-veinal pattern.
Garden Heuchera with purple or black foliage (1c) make a striking statement in the garden. As with other black-leaved plants, these look better as a specimen plant, an edging plant, or as a color contrast to a white or yellow plant rather than as a mass planting. Our favorite purple-leaved Heuchera here at Plant Delights Nursery and Juniper Level Botanic Garden are the heat tolerant cultivars Heuchera ‘Obsidian’ and Heuchera ‘Frosted Violet’. These are both improvements on the industry standard ‘Palace Purple’.
Garden Heuchera with red or bronze foliage (1d) are very interesting because the represent a color breakthrough. This group of Heuchera often changes color throughout the season. The red or bronze color is usually best early in the season and the plants ‘green-out’ as the temperature warms up. Breeders are working intently to make these colors stick around all year, or to have the colors change in an attractive manner. At Plant Delights Nursery and Juniper Level Botanic Garden we have several notable red and bronze cultivars. Heuchera ‘Caramel’ is very tolerant of heat and humidity. The leaves change from butterscotch to peachy-orange as the season progresses. Heuchera ‘Georgia Peach’ is also very heat tolerant and has peachy red leaves with dark red veins. Heuchera ‘Miracle’ leaves start off chartreuse. In the fall they develop red veins and late in the winter the whole leaf turns light red with a chartreuse edge. Similarly, Heuchera ‘Tiramisu’ emerges amber/chartreuse, develops red veins in the summer, which spread to form red leaves with a chartreuse border in the winter. Heuchera ‘Southern Comfort’ leaves emerge an peachy-orange color and shift to amber-orange and then to coral-orange in the winter.
Garden Heuchera with chartreuse or yellow foliage (1e) are beacons of brightness in the garden. As with the purple-leaved varieties, these look best as specimens or as a border edging. These often emerge bright and darken during the season. Our favorite chartreuse-leaved Coral Bells here at Plant Delights Nursery and Juniper Level Botanic Garden are the golden yellow Heuchera ‘Citronelle’, and Heuchera ‘Pistache’ which emerges charteuse and changes to lime-green as the season progresses.