Also known as western coolwort, foam flower is an attractive perennial with leafy stems from 15-40 cm high and numerous basal leaves. The stems and leaves are puberulent to hirsute and glandular. The single or clustered stems are erect or spreading. The leaves are like miniature maple leaves. The margins are 3-5 lobed, with toothed edges. The lobes are cut 1/4-1/2 the distance into the middle of the blade above the upper lobes. The basal leaves are up to 12 cm wide and 8 cm long with a heart-shaped base. The upper leaves are similar but smaller with shorter petioles and only 3 lobes. This variety is different from variety trifoliata in that the blade is simple, rather than compound ternate blades of the latter species.
The inflorescence is an open raceme of small white flowers. The white to reddish petals are linear in shape and fringed at the tips and are longer than the calyx lobes. The calyx is 1.5-3 mm long with the lobes about three times longer than the tube. .
Foam flower grows easily in thicker, moist woodland soils and makes an attractive ground cover with tiny white blooms in mid to late spring. The foliage is evergreen, at least west of the Cascade Mts. The latter variety is also less slender in form and more pubescent.
Foamflower, Foam Flower: Tiarella trifoliata var. laciniata - Basal and stem leaves have 3 leaflets. Each leaflet is cleft more than 1/2 the way into the middle. Flowers white, tiny, in a loose panicle.
Trefoil False Mitrewort, Trefoil Foamflower: Tiarella trifoliata var. trifoliata - Basal and stem leaves have 3 leaflets. Each leaflet is cleft less than 1/2 the way into the middle. Flowers white, tiny, in a loose panicle.
Coolwort, Foamflower, Foam Flower, One-leaf Foamflower: Tiarella trifoliata var. unifoliata (Synonyms: Tiarella trifoliata ssp. unifoliata, Tiarella unifoliata) - Basal and stem leaves simple, maple-leaf shaped with several lobes. Flowers white, tiny, in a loose panicle.
The foam flower may be found in moist shady woods and along stream banks.
The foam flower may be found from southern Alaska south through the Cascade and Olympic Mts. to Santa Cruz County, CA. It may be found eastward to Alberta and south to western Montana, northern Idaho, and northeast Oregon.