Coral bells (Heuchera spp.) earned their common name with the color and shape of their dainty flowers, which have a slender, bell shape and come in shades of warm pink, red and white. They grow readily with minimal upkeep or care and will last for many years in most gardens. Coral bells grow best when properly sited and given routine care early on to help them establish a deep, productive root system.
The Heuchera genus contains many species and dozens of cultivars, and most grow well in U.S. Department of Agriculture plant hardiness zones 3 through 8, although their hardiness varies by species. Hairy alumroot (Heuchera villosa) tolerates more heat and will grow in USDA zones 5 through 9, while alpine heuchera (Heuchera rubescens) requires a cooler climate and grows in USDA zones 3 through 7.
Choosing the correct growing conditions for coral bells makes the difference between a plant that survives and one that thrives. Full sun is best in cooler climates with mild weather, while a spot in light shade is a better choice in areas with hot summers. Even in hot climates, the plants need full sun for two to three hours daily to preserve leaf color and dense growth habit. Coral bells adapt to different soil compositions, but they perform best in fast-draining and moderately fertile soil with a pH between 5.8 and 6.2.
The correct planting practices give coral bells a good start in your garden. Plant in spring in colder climates and in fall in warm-winter climates. Amend sandy or clay-based soil with a 2- to 3-inch layer of pine bark humus or other organic matter worked into the top 6 to 8 inches. If the soil is depleted or especially poor, work granular, 12-6-6 ratio fertilizer into the soil at a rate of 2 pounds per 100 square feet at the same time as the amendment. Plant the coral bells 1 to 2 feet apart with the base of the foliage whorl even with or slightly above the surrounding soil.
Soil Moisture and Fertilizer
Once established, many coral bell species and cultivars are moderately drought-tolerant, but most look better and live longer with regular watering. Provide 1 inch of water weekly during the summer if no rain falls for longer than a week. You generally don't need to water the plants in fall or winter. Annual fertilizer applications each spring help encourage abundant foliage and flower production. Fertilize coral bells with general-purpose, 10-10-10 ratio fertilizer or blooming fertilizer with an N-P-K number of 5-10-5. Apply it to wet soil at a rate of 1/2 pound per 100 square feet of area.
Division and Rejuvenation
Over time, coral bells suffer age-related decline. Their blooming and foliage production decreases and they take on a permanently thin, ratty appearance. Division every three to four years rejuvenates older, less productive coral bells while increasing the number of plants in your bed. Dig up the old coral bells plant and cut it into three or four pieces, each with an equal share of roots and new shoots. Discard the old, woody center of the plant. Replant the divisions into the same bed 1 to 2 feet apart. Care for them as you would a normal transplant and watch for renewed growth as the weather warms.