Threeleaf foamflower lights up dark, damp woods with sprays of tiny white flowers that seem to hover above the ground like foam. The flowers are so small that their thread-like petals look much like the stamens beside them, and they hang in a narrow, open cluster from a slender stalk 8 to 20 inches tall.
Below the flowers sits a clump of long-stalked leaves. In the typical form each leaf is split into three toothed leaflets, but the plant is variable. One variety has a single lobed leaf, and another has leaflets cut almost to the base. In British Columbia the three-leaflet form mostly grows at lower elevations and the single-leaf form higher up, with the deeply cut form arising where the two meet and cross.
The seed capsules are odd too. Each splits into two unequal halves, one about twice as long as the other. Foamflower ranges from Alaska to California and east to the northern Rockies. Look for it along streams, in moist forest and in shady meadows from the lowlands to the subalpine, in bloom from late spring through summer.
How to identify it
Heart-shaped basal leaves on long stalks are usually divided into three toothed leaflets, though some plants have a single lobed leaf. A slender, glandular-hairy stem 8 to 20 inches tall carries a narrow, open cluster of tiny white flowers with thread-like petals. Seed capsules split into two unequal parts.
Look-alikes
Fringe cups grows in the same damp woods but has larger, cup-shaped flowers with fringed petals on a stouter spike. Piggyback plant has brownish purple flowers and leaves that are lobed but not split into leaflets.
Habitat
Moist forests, streambanks and shady meadows, from the lowlands to the subalpine.
Sightings in the forest
365 research-grade sightings in Mt. Hood National Forest on iNaturalist, most recently on October 10, 2026. See them on iNaturalist →