Heart-leaf Foamflower is a native erect perennial forb that has a flowering stem growing to 14 inches high.
The leaves are basal, heart shape at the base, with an acute tip and then with 5 to 7 palmately divided shallow lobes. The leaf stalks have glandular hair, some dense. The leaf surfaces usually have hair along the veins. The upper surface is a dark green, sometimes with purplish-brown mottling, the underside is much paler in color. Leaves on the flowering stem are absent or reduced to 1 smaller leaf.
The inflorescence is an upright raceme of 5 to 70 stalked flowers rising above the basal leaves. It is hairy like the leaf stalks.
The flowers are 5-parted with a bell shaped hypanthium, 5 whitish to pinkish petals that are ovate to lanceolate in shape, tips 3-toothed and a narrowed clawed base. [NOTE: Varieties are available in the nursery trade for the home garden and finding a true T. cordifolia with petals that have 3-toothed tips may be difficult]. The five sepals are of the same color but sometimes more pinkish while the petals remain white. These are spreading outward in flower and reflexed back in the fruiting state. The lobes of the calyx (the sepals) and the flower stalk are hairy. There are 10 very conspicuous stamens with white linear filaments and yellow oval anthers, two styles. Styles and stamens are well exerted from the calyx making a feathery or 'foamy' appearance. Flower buds are usually pinkish.
Seed: Fertile flowers produce a 2-valved (chambered) seed capsule that is winged. One of the valves is 1.5 to 2x longer than the other. They contain 4 to 15 shiny black ellipsoid shaped seeds. The wings on the capsule allows for wind dispersion of the seeds. The capsule splits apart along the inside seam.
Habitat: Foamflower grows from a rhizomatous root system that sometimes produces stolons for vegetative growth. Foamflower requires moist to moderately moist soils with partial sun to light shade such as found in forests, woody marsh edges. Full sun will burn the plants. It prefers moisture and partial shade. Works well as an understory plant in dappled shade. In warmer climate zones the plant will be evergreen. Plants can be propagated by root division every few years in spring or autumn.
Names: The genus Tiarella, is from two Latin words, tiara, meaning 'turban' and ella, meaning 'diminutive', which together refer to the shape of the seed capsule. The species name, cordifolia, is also from the Latin and refers to the heart shaped leaves. The author name for the plant classification - 'L.' is for Carl Linnaeus (1707-1778), Swedish botanist and the developer of the binomial nomenclature of modern taxonomy.
Comparisons: There is one other species of Tiarella that is similar, T. trifoliata, but there the flowering stem is not a raceme but a branching panicle, there are up to 5 leaves on the flowering stem and the petals are not toothed. The two species will not be found together unless planted together, as T. trifoliata is a species on the western edge of North America and T. cordifolia is an eastern plant.
Above: 1st photo - Foamflower can be found blooming from early May until late summer mainly on the path through the bog and also on Violet Trail. 2nd photo - A flower raceme with flowers having the true-to-species 3-tooth petals.Photo ©Thomas G. Barnes, USDA-NRCS Plants Database. 3rd photo - Seed capsules formed by early July. Note the large wing.
Below: The color can vary slightly as these with a pinkish tinge indicate.
Below: 1st photo - The lobed leaf with heart shaped base. 2nd photo - All leaves of the plant are basal except one as shown below on the flower stem.
Below: 1st photo - Sometimes the leaves in certain plants have a purplish coloration in the veining. 2nd photo - A flowering stem may occasionally have one small leaf as shown.
Below: 1st photo - An historic photo of May 31, 1952 taken by Martha Crone, of the bog path showing a massed bed of Foamflower that does not exist today. (Photo #3094, Martha Crone Collection, Minnesota Historical Society.) 2nd photo - The same area on June 5, 2008. Planting masses of the same species was common in the Garden at Martha Crones times. Today species are interwoven into the a more diverse group when planted.
Notes: Eloise Butler recorded obtaining specimens of Heart-leaf Foamflower in 1909 and again on April 30, 1912 from Gillett's Nursery in Southwick, Mass. This plant was listed on Martha Crone's 1951 inventory of plants in the Garden at that time. Foam Flower has been in the Garden continuously and replanted when necessary, as recently as 2012. T. cordifolia is generally considered to be not native to Minnesota; specimens have been collected only from Stearns County between 1978 and 1998 in Fairhaven Township; those may have been planted or are they a remnant of a long lost population?? The MN DNR does not list any current county populations. It is known in several NE Wisconsin counties, far from Minnesota and is considered rare in that state. Its native range in the US is generally east of the Ohio River although Wisconsin reports it as native in those several counties, but endangered. In Canada it is known from New Brunswick, Nova Scotia, Ontario and Quebec.
References: Plant characteristics are generally from sources 1A, 32, W2, W3, W7 & W8 plus others as specifically applied. Distribution principally from W1, W2 and 28C. Planting history generally from 1, 4 & 4a. Other sources by specific reference. See Reference List for details.
Friends of the Wild Flower Garden, Inc. Text and photos are by G. D. Bebeau unless otherwise credited. "www.friendsofthewildflowergarden.org"