Scutellaria incana aka Hoary Skullcap

Scutellaria incana is a perennial wildflower in the mint family. Gardeners call it downy skullcap or hoary skullcap. It comes from the north-central and eastern United States. In the wild, it grows in dry, shaded forests and open woods. It also grows on slopes and along streambanks. The plant forms upright clumps and loses its foliage each year.

Garden plants reach about 2–3.3 feet [0.6–1 metre] tall. Some reach 3.9 feet [1.2 metres], as the RHS notes. Clumps spread about 1.5–2 feet [0.45–0.6 metres] wide. Growth proceeds at a moderate rate. Fine white hairs coat the green, square stems, which lack scent. The simple green leaves grow in opposite pairs. They have an egg-shaped outline and rounded teeth along their edges. Small white hairs cover the leaf undersides. Leaves can reach 3 inches long and 1.5 inches wide.

Loose racemes hold the blue to purple flowers on branching stems. Each flower has a tube and two lips. The upper lip forms a hood over the throat. A white patch marks the lower lip near the throat. Fine hairs also cover the flowers. Bloom falls mainly in summer, with timing varying among sources. The RHS gives June through September; NC State gives July through August. Chicago lists a broader May through October window. Brown capsules follow from August through October and hold small nutlets. Each capsule loses its top to release the seeds. Its lower, scoop-shaped part stays on the plant.

Grow downy skullcap in soil that drains well. It prefers moderate moisture but copes with dry soil and drought. It also tolerates heat, poor soil, sand, and clay. Acid to neutral soil suits it. Full sun works where the soil retains enough moisture. Part shade suits drier sites, and it also accepts dappled light. Sources list USDA zones 4–9 and UK hardiness H7. Divide clumps in spring or autumn, or sow seeds in autumn. Cut back old growth at the end of the year.

Use this plant in borders, meadows, cottage gardens, or open woodland. Its flowers draw bees and butterflies, and moth larvae use it as a host. Birds also visit the plant. Deer and rabbits tend to avoid its bitter leaves. Care needs are low, with no major pest or disease problems reported. Aphids may occur, though the plant is generally free of disease. The supplied sources do not establish human edibility or toxicity.