Heuchera micrantha aka Crevice Alumroot

Heuchera micrantha is a perennial in the saxifrage family. Its common names include crevice alumroot and small-leaved alum root. Kew places its native range from the northwestern United States to California. Plants For A Future also lists British Columbia. It grows on damp woodland banks among humus and rocks. Other sites include gravel banks and cracks in rock. These habitats range from low ground to the subalpine zone.

The plant forms a low, leafy clump and keeps its leaves year-round. Garden plants reach about 0.3–1.6 feet [0.1–0.5 metres] tall and wide. The leaves have lobes and toothed edges. Fine hairs often cover their surfaces. Leaf colour varies across the species. Plants may have green, reddish, or purple leaves. Small white or pink flowers rise well above the leaves. Their loose sprays give a light effect in the garden. Flowering falls in late spring and early summer.

Choose a light or medium soil that drains well. The RHS lists sand, loam, and chalk as suitable soil types. It gives neutral soil as the preferred pH. Plants grow in full sun or light shade. They tolerate dry to moist soil and resist drought. The RHS rates the species H5 for UK hardiness. Plants For A Future lists USDA zones 4–8. Plants take two to five years to reach full size. Divide and replant clumps every three to four years to keep growth strong. Seeds and autumn division offer ways to raise more plants. Remove flower stems once their blooms fade.

Crevice alumroot suits rock gardens, gravel beds, and garden edges. It also fits coastal sites, cottage gardens, and containers. Its low clumps can provide ground cover in woodland gardens. Plants For A Future suggests spacing plants about 1 foot [0.3 metres] apart. Leaf colour and raised flower sprays provide contrasting forms. Watch for vine weevil and leaf and bud eelworm. Heuchera rust and leafy gall can also affect plants.

Plants For A Future records cooked young leaves as edible. It also notes that their taste has little appeal. The source reports no known hazards, though this does not prove complete safety. It records medicinal uses of the root, including astringent and antiseptic uses. These records do not establish that such treatments work. The root also serves as an alum substitute for fixing dyes. Plants For A Future does not flag the species as weedy.