Coral Bells (Heuchera)

Alumroot, Coral Bells, Heuchera

With fantastic foliage and fun colors, heucheras (also called coral bells) are the perfect plant for those less sunny spots! Planted in early fall or spring, this perennial plant is also rabbit- and deer-resistant. Learn how to grow heucheras.

I. Appearance and Characteristics 

Heuchera is a genus of largely evergreen perennial plants in the family Saxifragaceae, all native to North America. Common names include alumroot and coral bells.

Heuchera have palmately lobed leaves on long petioles, and a thick, woody rootstock. The genus was named after Johann Heinrich von Heucher (1677–1746), an 18th-century German physician, and Professor at Wittenberg University. There are approximately 37 species, but the taxonomy of the genus is difficult because the species often integrate with one another, hybridization is common, and the flowers change markedly in proportion as they develop.

Alumroot species grow in varied habitats, so some species look quite different from one another, and have varying preferences regarding temperature, soil, and other natural factors. H. maxima is found on the Channel Islands of California, where it grows on rocky, windy, saline-washed ocean shores, and H. sanguinea, called coral bells because of its cerise flowers, can be found in the warm, dry canyons of Mexico and adjacent New Mexico and Arizona. In the Mid-Atlantic region of the United States, the plants grow best in shade.

II. How to Grow and Care

Sunlight

Coral bells will perform better when grown under full or partial shade. Ensure your plant is getting enough bright, filtered, indirect light wherever it is located.

Exposing your coral bell plant continuously to direct sunlight is dangerous as it can cause scorching of its leaves and also lead to discoloration.

Coral bells grown indoors will appreciate an area that is bright but at the same time not exposed to direct sunlight. A good location for the plant would be close to a south-facing window, as this area is protected from direct sunlight.

Temperature and Humidity

Coral bells are hardy in USDA hardiness zones 4a to 9a, although the exact hardiness range does depend on the variety you’re growing and its parentage. Some Heucheras are only hardy to zone 7, while others do well in cold but don’t perform well south of zone 6. Most coral bells prefer relatively dry air, but Heuchera villosa, a native of the southeastern U.S., thrives on both heat and high humidity.3

In regions with frigid winters, coral bells crowns can heave above the soil line in the winter. Winter mulching will help prevent the freezing/thawing cycle that pushes the plants up, and you should check periodically to make sure the roots are not exposed.

Watering

This plant has medium water needs and likes consistently moist soil. Established plants will tolerate some drought, but an inch of water per week is the best way to keep them happy. If you grow your coral bells in full sun, plan to give them extra water—their shallow roots will need extra moisture during hot, sunny days.

Soil

Coral bells perform better in well-drained soil that’s capable of retaining moisture, slightly acidic with a pH level of around 6 and 7, and also rich in humus.

When planting in pots, use a potting mix made from a combination of soil, perlite, coco peat, and organic compost. This will help provide the plant with sufficient nutrients for the first few months.

When planting directly in the soil, make certain that your growing area has an adequate irrigation system. Avoid soggy and waterlogged soils, as these are dangerous for the plant.

Fertilizing

Feed coral bells in the spring with a one-half-inch layer of compost or a light amount of slow-release fertilizer. This plant has light feeding needs; you should avoid heavy applications of quick-release fertilizers, as this will inhibit flowering. Container-grown coral bells benefit from feeding with a water-soluble fertilizer to replenish nutrients that leach from the soil. For the amount, follow the product label instructions.

Pruning

As a low-maintenance plant, coral bells do not require regular pruning. However, if you wish to control the size of the plant, you can prune it to your taste.

Deadheading can also be carried out in order to encourage the plant to channel its energy into putting out more leaves.

For a cleaner-looking plant, cut off all dead, old, and infected leaves and stems.

Propagation

Coral bells are most often propagated by dividing the root clumps. Either fall or spring division will work, though many gardeners prefer fall. Heuchera plants often produce small offsets around the parent plant, and it’s an easy matter to carefully dig up these offsets and replant them. The root crowns of the divisions should be planted so they are just barely covered with soil.

Heuchera plants are fairly short-lived, and this division should be done every three or four years to prevent them from dying out. To propagate mature plants:

  • Dig up the entire root clump with a shovel in fall or spring.
  • Cut the root clump into pieces, each having several growth shoots. The woody center portion can be discarded.
  • Prepare new planting sites by blending in plenty of compost or peat moss, then replant the divisions, just barely covering the root crowns.

Grow from Seed

You can start coral bells from seed, but results can be irregular if you are collecting seeds from hybrid plants. Commercial seeds will produce more predictable results. If you want to propagate plants by collecting seeds, it’s best to start with pure species plants rather than nursery hybrids. Pure species are easiest to obtain from specialty nurseries or online retailers.

When starting the seed, sprinkle the seed on the surface of the soil in late fall or early spring, making sure not to cover the seed as they need light to germinate. You can also start seeds indoors a couple of months before you plan to transplant. Coral bells seeds take two to eight weeks to germinate.

Once established, harden off the plants for 10 days, then transplant the seedlings outdoors after all danger of frost has passed. You can plant container-grown coral bells any time after the danger of frost has passed. Keep them well-watered their first year—other than that, they shouldn’t require more than some relief from the extreme heat and rich, well-draining soil.

Pests and Diseases

Common Pests & Plant Diseases

Coral bells is usually a fairly carefree plant, but it can be affected by various fungal diseases, including powdery mildew, rust, and bacterial leaf spot.

Potential insect problems include weevils and foliar nematodes. The larvae of the black vine weevil can bore into the crowns and roots of coral bells in late summer or early fall, causing infected plants to wilt and droop. You should be able to see the larvae on the plant and remove them by hand and destroy them. If an infection persists, treat your plants with a mild insecticide or neem oil.

Common Problems 

Coral bells are generally quite easy to grow, but there are some common cultural problems you may encounter:

Scalded Leaves

Most varieties of coral bells are not keen about growing in full sun, and they may exhibit burned, scorched leaves if they get too much sun, especially in climates with hot summers. Giving plants extra water during hot spells can minimize this scorching.

Plants Die Out After a Few Years

It’s sometimes disappointing when a thriving coral bells plant suddenly declines, but this is rather normal, as these are short-lived perennials that usually live only four or five years. You can prolong the lifespan by dividing root clumps every three or four years, which will provide new plants to continue the lineage.

Plants Lift Out of the Ground

Coral bells have shallow root systems with crowns that are slightly exposed. In cold climates, frost heaving can push them out of the ground entirely, which will require you to replant them. A layer of mulch applied just after the ground freezes may help prevent heaving due to repeated freeze-thaw cycles.

Potting and Repotting 

Although it’s not typical to grow perennials such as coral bells in containers, it certainly can be done, and this plant does quite well when grown that way. Choose a container that has good drainage and a potting mix that drains freely. When grown in containers, keep the root crown slightly higher than the soil level. If you want to overwinter these plants in pots, they will need to be moved to a protected location to shield them from cold winter temperatures. During the winter months, withhold water and allow the plants to go dormant.7

While the spectacular foliage might tempt you to try growing coral bells as a houseplant, they do not lend themselves to this use. These woodland plants can do fine in outdoor containers where they receive a dormant period over winter, but they rarely are successful as permanent indoor houseplants.

Overwintering

In warmer climates, this plant often remains evergreen through the winter. Because the roots are shallow, coral bells can be prone to winter root heaving in colder climates. A light mulch over the plants can prevent this. In other regions, overwintering simply involves cleaning up plant debris to prevent fungi from overwintering.

III. Uses and Benefits 

Native American peoples used some Heuchera species medicinally. The Tlingit used H. glabra as an herbal remedy for inflammation of the testicles caused by syphilis. To the Navajo, H. novamexicana was a panacea and a pain reliever. The roots of H. cylindrica had a variety of medicinal uses among the Blackfoot, Flathead, Kutenai, Okanagan, Colville, and Shuswap.

Coral Bells (Heuchera) Details

Common name Alumroot, Coral Bells, Heuchera
Botanical name Heuchera
Plant type Herbaceous Perennial
Hardiness zone 3a, 3b, 4a, 4b, 5a, 5b, 6a, 6b, 7a, 7b, 8a, 8b, 9a, 9b
Growth rate Medium
Harvest time Fall
Height 0 ft. 6 in. - 1 ft. 8 in.
Width 0 ft. 6 in. - 1 ft. 8 in.
Sunlight Full sun (6 or more hours of direct sunlight a day)
Soil condition High Organic Matter
Flower color Orange
Leaf color Blue