VERMONT ORGANICS RECLAMATION
It has been said that native plants are frequently overlooked, and exotic species are more readily accepted by consumers. This trend is changing, but perhaps Tiarella cordifolia (heartleaf foamflower) has experienced an even greater indignity as it is officially endangered in two U.S. states – New Jersey and Wisconsin. This wonderful plant has been long known to horticulture, and provides excellent native ground cover. John Bartram, an early American botanist, horticulturalist and explorer, wrote it was common in the woods in the 1700s, particularly along the Raritan River in New Jersey. It’s easy to grow and thrives in just about any landscape situation – whether on a bank, in a rock garden or woods edge, it requires low maintenance and grows heartily. In addition to being a beautiful groundcover, T. cordifolia also provides added benefits to the environment.
The flowering ability of this native perennial plant is spectacular in season; typically four to six weeks of bloom can be expected. Clump-forming types usually have a greater number of racemes than running types, and it is possible to have 100 to 200 racemes per established clump. Rebloom can occur on plants when cooler temperatures occur in fall. T. cordifolia plants are also easy to force into bloom in a cool greenhouse out of season. Flowers are typically white, but some selections are available with pink sepals.
Tiarella cordifolia can be either clump-forming or those with runners (stolons). Typical clump-forming plants will be 6 to 8 inches tall, and flowers borne on racemes can be up to 24 inches in height, but usually are 12 to 15 inches tall. A clump-forming foamflower’s foliar width is usually 12 to 18 inches for a mature plant. Running individuals are a bit more variable in spreading ability, as this depends on the stolon internode length. This characteristic allows running plants the capability of forming an excellent groundcover in moist shade.
Another excellent ornamental feature of this great genus is the evergreen foliage. The leaves persist through the winter, taking on color usually in the red and yellow range as nights get cooler come September and October in the Mid-Atlantic region and later further south. This will vary by site and exposure, as well as temperature. If your region is usually snow covered, this winter color may not be noticeable. Cultivars and selections have a usual pattern in this respect; a mixed array of species generated from seed would be highly variable in fall and winter color.
VERMONT ORGANICS RECLAMATION
Foliage provides great contrast with other shade-loving plants, such as Heuchera, Heucherella and Phlox blooming as a contrast to the white flowers in spring. Many variations in leaf shape exist, typically maple or ivy shaped, while some cultivars and selections (or individuals due to the vast diversity) are deeply dissected. Color variation in leaf exists, as well. Anthocyanin pigment is distributed along the leaf veins, or in some cases covering the leaf surface, causing a lovely red contrast in the leaf and planting.
Growing in zones 3 to 9, foamflower’s native distribution extended from Hudson Bay and Maine to the northern counties of Georgia, Alabama and Mississippi, as well as most states east of the Mississippi except Illinois and Indiana. Today, T. cordifolia and its selections and cultivars are being cultivated all around the world from Moscow to Northern California. Further, they’re growing successfully out of the original range, as in Minnesota, Missouri and even at the Dallas Arboretum in Texas.
Landscape uses include mass plantings with a diverse display of groundcover for shady areas under trees and shrubs or under the forest canopy and at woods edge. Specimen plants can be showcased in shade gardens or used as a component in containers, baskets and urns. They also can be forced easily for indoor applications and grow in almost any soil type if amended with organic matter.
Tiarella cordifolia complements ecological applications as part of a streamside matrix of roots to help improve our nation’s water quality by controlling soil erosion and restoring stream banks. They are also capable of taking up a fair bit of nitrogen in a riparian system. In addition, the plant also feeds about five families of bees, which are emerging for the season about the time of bloom.
Tiarella cordifolia is a great addition to any landscape, as it provides not only beauty but restores and protects our ecosystem.
Sinclair A. Adam, Jr.
Keith E. Friend
Vermont Organics Reclamation, St. Albans, Vt.