This genus is comprised of a dozen species of erect, deciduous, rhizomatous perennials from moist, sunny sites in eastern North America. Their square stems of often toothed leaves are topped by racemes of 2-lipped flowers that stay in a new position if they are moved on the stalks, giving rise to the name “obedient plant.” They are attractive in a border, but some are aggressive growers.
Noteworthy CharacteristicsTubular, 2-lipped flowers in shades of purple, pink, or white. Good cut flowers. Some species are invasive.
CarePhysostegia prefer fertile, reliably moist soil in part shade or full sun. Some species may need restraint.
PropagationSow seed in containers in a cold frame in fall, or divide in winter or early spring before new growth begins.
ProblemsSometimes bothered by slugs and rust.
