Bringing bright blooms and lasting foliage interest to shadier spaces, Tiarella (tee-uh-RELL-uh), of the Saxifrage family, Saxifragaceae, is a unique genus of seven species, largely native to North America, including the Minnesota native heartleaf foamflower, Tiarella cordifolia. Though their exact lineage and species characteristics are still debated, Tiarella, also known as foamflower, are generally identified by three main characteristics: the presence or absence of stolons, the size and shape of their basal (bottom) leaves, and the presence or absence of stem (cauline) leaves; however, popular garden cultivars are virtually all hybrids of largely uncertain lineage, bred to emphasize their dramatic foliage and showy blooms.
Maturing up to 12-18” tall and wide including the height of their blooms, Tiarella grow as a tidy mound or slow-spreading cluster depending on species and variety, shining in woodland gardens and low shady borders. Tiarella are phenomenal for underplanting shrubs, excellent when massed as a groundcover, and perfect for pathway edging to best admire their spring flowers and showy foliage up close. Aptly named, foamflower bloom from mid-spring to early summer, producing frothy bottlebrush white or rosy pink flower spikes on erect stems above the foliage, with a wonderful mild, sweet fragrance. Racemes are comprised of upwards of fifty star-like flowers, each with five sepals, five petals, and ten long stamens that extend beyond the petals, giving the blooms a feather-like appearance. After blooming, spent spikes should be removed to promote dense, bushy foliage growth through the summer months.
Prized not only for its visual appeal, but also its resistance to deer and rabbit feeding, Tiarella boasts some of the most stunning foliage around in shadier gardens, brightening up even deeply shaded sites. Light green in color with dramatic, contrasting deep purple midvein accents, leaves of three to five lobes make a stunning low clump great for adding contrast in shady beds, with some varieties, such as ‘Candy Striper,’ putting on an a show with dramatic, deeply lobed, almost finger-like large leaves that shine all season long. Continuing their appeal long after blooms have faded, Tiarella add to the fall landscape as well, often taking on a beautiful bronze-purple color in cooler temperatures.
Thriving in part sun or shaded sites, including deep shade, Tiarella performs well in moist, well-drained soils rich in organic matter. Foamflower is an excellent low maintenance shady addition, just be sure that plants are not allowed to dry out completely and avoid planting in areas where plants may experience extended wet periods while dormant.