Time of bloom: June to August.
Seed-time: August to October.
Range: Minnesota to British Columbia, southward to Arkansas, Utah, and California. Habitat: Moist soil; wet meadows and along streams.
Plants of this species are sometimes smooth, but usually they are finely white-woolly all over, even to the flowers, of which the calyx is densely so. Stems simple, stout, one to two and a half feet tall. Leaves opposite, thick, broadly ovate to heart-shaped, grayish green, with large veins and short, stout petioles. Umbels many-flowered, the corollas greenish purple, the pedicels and the stout peduncle softly hairy. Follicles plump, three or four inches long, covered with soft, spinous processes, and also densely white-woolly, held erect or slightly spreading on recurved pedicels.
Drainage of the ground. Uprooting with grubbing-hoe or plow, or such close and persistent cutting as to rob the perennial roots of all sustenance.