Submitted by Natalie R. Bumgarner, Assistant Professor of Residential and Consumer Horticulture and Tennessee Extension Master Gardener Coordinator
One of the joys of shade gardening is the opportunity to have a taste of Tennessee woodlands in our own backyards. Two common forest flowers found in Tennessee are Heuchera and Tiarella. Better known as coral bells or alum root, Heuchera has several species that vary in distribution across the state and are more common in Middle and East Tennessee. Tiarella, or foamflower, is most common in East Tennessee. Many selections of these and other species not native to Tennessee can be found in nurseries; however, as close members of the Saxifragaceae family, some of their respective, distinct attributes can be found in the intergeneric cross x Heucherella. This hybrid commonly goes by the name foamy bells in the U.S., which gets a nod for logic, but receives no naming bonus points for creativity.
As a general statement, foamy bells bring together the flowering look of coral bells and some of leaf patterns and shapes of foamflower. Often you’ll see these crosses with dark patterns in the center of the leaves or a more deeply cut or lobed leaf than most coral bells. In reality, this is an oversimplification. You can now find bronze and purple leaves and even silver tones in foamy bells (like ‘Cracked Ice’) and a range of flower colors and characteristics. We tend to focus on plant color and shape for obvious reasons, but the diversity in native species in both of these parents provides the opportunity for crosses that thrive in a range of conditions.
Site selection and management are important to enjoying foamy bells over the long term. When selecting a site, keep in mind that often these plants reside natively in the understory of forests.
Foamflower, more than coral bells, tends to prefer very moist locations and is found on stream banks with higher levels of organic matter. Some coral bells have more ability to thrive in more stressful environments. So, such parents can be chosen to bring to the cross better tolerance of hot and humid summer conditions, which were often lacking in early Heucherella introductions. Recent breeding efforts have used Heuchera villosa as a parent, which was an important step in delivering foamy bells that perform better in Tennessee-type climates. Cultivar names, such as ‘Alabama Sunrise’ and ‘Sweet Tea’ are some examples of these crosses, and their names give clues as to potential adaptation to our types of summers. Light shade to part sun is going to be a good choice for most Tennessee gardens, and moderate rather than high light levels may increase foliage color contrasts for these late spring to early summer bloomers. Dividing the plants every few years will also maintain their longevity in the garden.
Good soil drainage, though, is essential whichever of these species or cultivars you are growing. Poor drainage, especially in the winter, can damage these plants. So, avoid sites where heavy soils retain water around the plant. Raised beds can increase drainage, and container growing can be an excellent option for some of these beautiful specimens. In fact, some of the most impressive displays I have seen were on porches in containers where moisture and light can be tailored.
Foamy bells and their cousins can be found at all three locations of the UT Gardens. Stroll from the main entrance of the Knoxville gardens toward the Children’s Garden and you’ll find some in those shady plantings along the path, while they are can be found in some slightly protected sites around the building in Crossville. In Jackson, you can find Heucherella and many other shade options around the gazebo.
So, select a welcoming spot in your garden (or porch), ensure good drainage and bring a bit of the hills home with a Heucherella.
The UT Gardens includes plant collections located in Knoxville, Jackson and Crossville. Designated as the official botanical garden for the State of Tennessee, the collections are part of the UT Institute of Agriculture. The Gardens’ mission is to foster appreciation, education and stewardship of plants through garden displays, educational programs and research trials. The Gardens are open during all seasons and free to the public. For more information, see the Gardens website: ag.tennessee.edu/utg.