Known since pre-Christian times as a source for deep blue dye (it is extracted from the foliage), this plant was probably imported into the U.S. by European colonists in the late 17th century. It quickly spread by seed and is now con- sidered a weed in many dry Western states. In the South, however, it's less likely to become weedy and makes a fine addition to a mixed herbaceous border. Bluish green, 8 inches-long basal leaves grow in clumps from a thick taproot. Flowers usually come in April and May of the second year, when the plant sends up 2- to 4 feet-tall stems tightly clasped by lance-shaped, blue- green leaves with white midveins; blossom stalks branch off near the stem tops, bearing large (up to 1 feet-wide) clusters of small, bright yellow blooms. Deep purplish black seedpods form after the flowers fade. Plant in well-drained soil; space 1 feet apart. Rarely bothered by pests or diseases.