Heart-leaved Foamflower (Tiarella cordifolia)

False Miterwort, Foamflower, Heart-leaved Foamflower, Coolwort

Heartleaf foamflower (Tiarella cordifolia) is a perennial plant that will grow to 36 cm tall. It has lobed heart-shaped leaves at the base and tall hairy stalks ascending from the base. From spring to summer white flowers bloom profusely along the stalks. It produces seeds in summer. It prefers moist soil with partial shade such as in woodland and forest areas.

I. Appearance and Characteristics 

Tiarella cordifolia, the heart-leaved foamflower, is a species of flowering plant in the family Saxifragaceae. The specific name cordifolia means “with heart-shaped leaves”, a characteristic shared by all taxa of Tiarella in eastern North America. It is also referred to as Allegheny foamflower, false miterwort, and coolwort.

Historically, the name Tiarella cordifolia has referred to the one and only species of Tiarella in eastern North America, but in 2021, the species was split into multiple taxa, which caused the name to have a different meaning. For clarity, the qualified name Tiarella cordifolia sensu stricto (abbreviated s.s.) refers to the new taxon while Tiarella cordifolia sensu lato refers to the old taxon.

Tiarella cordifolia sensu lato is wide-ranging across eastern North America while Tiarella cordifolia sensu stricto is narrowly confined to the East Coast of the United States. Cultivars of Tiarella are valued in horticulture for their erect stems of foamy cream-colored flowers.

Tiarella cordifolia sensu lato is a herbaceous, perennial plant with a scaly horizontal rhizome. The heart-shaped basal leaves have hairy stalks up to 20 cm (8 in) long. Both sides of the leaf blade have uniformly scattered hairs. The erect flowering stem is 15–40 cm (6–16 in) long, with a terminal raceme of 15–50 flowers. The flowers are white, small and feathery, giving the flower cluster a fuzzy appearance. Each flower has 5 sepals, 5 petals, and 10 long, slender stamens (which are longer than the petals). The two unequal seed capsules split along their inside seams, releasing several pitted seeds.

Some species of Tiarella produce leafy stolons (T. austrina, T. stolonifera) and some have stem leaves (T. nautila, T. austrina). Some species have relatively large basal leaves with an extended terminal lobe (T. austrina, T. nautila, T. wherryi). Tiarella cordifolia sensu stricto has none of these characteristics.

The heart-shaped basal leaves of Tiarella cordifolia sensu lato resemble those of species in other genera. For example, Tiarella is sometimes confused with Mitella diphylla, a closely related species that occurs over a similar range and habitat. If a plant lacks sufficient evidence of flowering, the orientation of the hairs on the basal leaf stalk may be used to distinguish the two species. All species of Tiarella in eastern North America have dense spreading hairs (outward-facing, angled 90 degrees) of various lengths while M. diphylla has long retrorse hairs (backward-facing, angled 45 degrees or less) sparsely distributed along its basal leaf stalk.

Tiarella cordifolia has gained the Royal Horticultural Society’s Award of Garden Merit. It spreads well by rhizomes, unlike other cultivars of Tiarella, but lacks the invasive tendencies of many more commonly employed groundcovers.

II. How to Grow and Care

Sunlight

Foamflower needs part shade to full shade. If there is any sun, it should be only morning sun.

Temperature and Humidity

As a plant native to temperate climates, foamflower is cold-hardy but not suitable for hot summer temperatures above zone 8.

Watering

Foamflower needs evenly moist conditions. It can withstand a short drought, but watering is required during extended dry periods.

Soil And Transplanting 

False Miterwort can do well in a wide variety of soil types, ranging from sand to clay; however, as with most plants, it will do best in light, airy, well-draining, fertile soil well-amended with humus and organic matter.

While this plant is not picky about pH levels, it will do best in soil that is slightly acidic or neutral (6.2-6.5).

When planting in containers, choose a container to allow the plant its full two-foot spread. When planting in the landscape, allow a distance of two feet between young plants.

If you choose to keep your Foamflower as a container plant, choose a setting that provides deep shade and good shelter from extreme heat or cold and high winds. When the plant is elevated from the ground, it is more sensitive to these environmental challenges. 

Fertilizing

When grown in the right soil, foamflower does not need fertilizer. However, it may benefit from the application of a complete fertilizer in early spring before the new growth starts. For the amount to use, follow product label instructions.

Propagation

You can propagate foamflower by dividing dense, well-established clumps in the late fall. Do this every few years to give the plants adequate air circulation and to make sure the soil is still well-draining. Simply do this:

  • Dig up clumps and gently, naturally separate into divisions.
  • Plant the divisions 1 to 2 feet apart where they will fill in the space.
  • Alternatively, remove some of the aboveground runners and apply rooting hormone to the ends to help them get established.
  • Replant runners right away in the ground and moisten soil.

How to Grow from Seed

If you are very patient, you can also start a foamflower from seed. Germination might be fast, but the seedlings will grow slowly. And remember—perennials don’t bloom in their first year. Take these easy steps:

  • Harvest small black seeds from pods about a month after the first bloom. Look for pods at the bottom of the stalks first.
  • Clean seeds and store them in sealed, refrigerated containers until you are ready to start them.
  • Start foamflower seeds indoors in flats about two months before the estimated last killing frost.
  • Transplant seedlings outdoors into their permanent home after that last killing frost.

Grooming And Maintenance

Keep Foamflower looking its best by planting it in a setting that protects it from harsh sun, high winds, and damaging weather. A natural woodland setting will provide just such an environment.

For the most part, this wildflower doesn’t need much in the way of maintenance. Remove dead or damaged foliage and spent blooms as needed.

If you want the plant to reseed itself, leave the blooms in place until seeds have formed and dropped.

Songbirds are very fond of seeds, so allowing your plants to go to seed will attract these friendly garden helpers to your yard.

Alternatively, you may gather seed before it drops to store or sow in a new location. You can either sow it immediately or store it in a cool, dry place and sow it in the spring.

Pests and Diseases

This hardy, carefree wildflower resists predation by rabbits and deer and has very few pest and disease problems when ideal growing conditions are met.

Overwatering and/or poor drainage can lead to root rot and problems with pests such as snails and slugs.

Most insect pests avoid the plant; however, plants with weakened conditions may be infested by foliar nematodes and/or black vine weevils. Use systemic pesticides to do away with black vine weevils.

For nematodes, the only way to treat them is to avoid them in the first place. Be sure to get your plants from reputable nurseries. Always follow best practices by inspecting plants carefully before bringing them home and quarantining them for a couple of weeks upon arrival.

III. Types of Foamflower

There are two varieties of foamflower:

  • Heartleaf foamflower (Tiarella cordifolia var. cordifolia) grows in dense clumps with runners and the leaves are heart-shaped, often with burgundy patches.
  • Wherry’s foamflower (Tiarella cordifolia var. collina, synonym: Tiarella wherryi) does not send out runners and the deeply lobed leaves resemble fig, oak, or maple leaves.
  • There are also several hybrids of Tiarella cordifolia, which is the native Eastern U.S. species, with the Western U.S. species of foamflower (Tiarella trifoliata), or with Asian foamflower (Tiarella polyphylla).

Here are the popular foamflower cultivars:

  • ‘Oakleaf’ has oak-like leaves and white flowers. The leaves turn red in the fall.
  • ‘Brandywine’ boasts glossy, heart-shaped leaves that have red veins. Flowers are creamy white, and the leaves turn bronze in the fall.
  • ‘Running Tapestry’ features red-speckled, heart-shaped leaves and white flowers. The plant sends out strawberry-like runners.
  • ‘Sugar and Spice’ has shiny, deeply lobed, lacy leaves that have a crimson marking in the middle. The flowers are pale pink and white.

IV. Uses and Benefits 

  • Naturalize

Allegheny Foamflower is a natural ground cover in a shady yard or garden. It is perfect for brightening a native plant garden or woodland setting. It’s a beautiful addition alongside a backyard pond or stream.

  • Conserve Soil & Water

Tiarella cordifolia is an excellent native plant alternative to invasive shady-place ground covers such as English Ivy.

It will do well in settings where soil conservation is needed. Its sturdy, complex root system battles erosion and captures water runoff.

  • Attract Pollinators

Foam Flowers are very attractive to hummingbirds, butterflies, bees, and other beneficial insects and pollinators, so this pretty, low-growing wildflower makes an excellent ground-layer addition to a butterfly or pollinator garden.

  • Create A Border

The plants’ dramatic, bright white blooms make it a good choice as a flowerbed border or path edging. Scented varieties make a lovely addition to a moon garden. 

  • Beautify Your Herb Garden

Because Coolwort has a number of uses in folk medicine, it can make a pretty addition to your herb garden.

  • Brighten Shady Spaces

Tiarella cordifolia is an excellent choice for fairly dry, deeply shaded settings under shrubs and trees. In deep shade, the plants’ moisture needs are lessened.

Heart-leaved Foamflower (Tiarella cordifolia) Details

Common name False Miterwort, Foamflower, Heart-leaved Foamflower, Coolwort
Botanical name Tiarella cordifolia
Plant type Ground Cover
Hardiness zone 3a, 3b, 4a, 4b, 5a, 5b, 6a, 6b, 7a, 7b, 8a, 8b
Growth rate Slow
Harvest time Spring
Height 0 ft. 5 in. - 1 ft. 0 in.
Width 0 ft. 5 in. - 1 ft. 0 in.
Sunlight Dappled Sunlight (Shade through upper canopy all day)
Soil condition High Organic Matter
Flower color Pink
Leaf color Green