Common Name: obedient plant
Type: Herbaceous perennial
Family: Lamiaceae
Zone: 3 to 9
Height: 1.00 to 1.50 feet
Spread: 1.50 to 2.00 feet
Bloom Time: June to September
Bloom Description: White
Sun: Full sun
Water: Medium
Maintenance: Medium
Suggested Use: Naturalize, Rain Garden
Flower: Showy
Attracts: Hummingbirds
Tolerate: Deer, Clay Soil
Culture
Easily grown in average, moist, acidic, well-drained soils in full sun. Stems tend to flop in rich soils, too much shade or hot summer temperatures. Taller plants may need staking. Tolerates wet soils and some part shade.
Noteworthy Characteristics
Physostegia virginiana, commonly called obedient plant or false dragonhead, is a rhizomatous perennial that is native to North America from Quebec to Manitoba south to Florida and New Mexico. In Missouri, it is commonly found in a variety of habitats including open meadows, prairies, stream banks, gravel bars, wooded bluff bases and railroad track right-of-ways (Steyermark). Tubular, two-lipped, snapdragon-like, pink to pale lilac flowers in upright terminal spikes (each to 12-18”) bloom throughout summer (late June-September) atop square stems rising to 2-4’ tall. Flowers bloom bottom to top on each spike, with each flower being subtended by a small leaf-like bract. Stems are clad with opposite, narrow-lanceolate, sharply-toothed leaves (to 3-6” long). Species plants are noted for being aggressive spreaders in the landscape by both rhizomes and self-seeding.
Genus name comes from the Greek words physa meaning bladder and stege meaning covering in reference to the calyces which inflate as they develop.
Specific epithet is in reference to the State of Virginia which is part of the native range for this plant.
Genus members are commonly called obedient plants because each individual flower will, upon being pushed in any one direction, temporarily remain in the new position as if it were hinged. Genus members are also commonly called false dragonhead because the flowers are suggestive of the flowers of dragonhead (Dracocephalum).
'Crystal Peak White' is a compact cultivar that rises to only 15" tall. It is noted for its (1) compact size, (2) short and sturdy upright stems that do not flop, (3) abundant blooms over a long summer period (July - September), and (4) pure white flowers that do not fade to brown as they age. As the cultivar name suggests, the flowers are pure white. Flowers bloom on each spike from bottom to top. Narrow, lanceolate leaves (to 4" long) have sharp-toothed edges. Plants will spread by rhizomes, but spread is reportedly less aggressive than that of species plants.
Problems
Rust is an occasional problem. Watch for aphids and spider mites.
Species plants can be an aggressive spreader.
Reportedly less aggressive than that of species plants.
Uses
Valued for its compact form and abundant white flowers. Borders. Naturalize in cottage gardens, wild gardens, prairies or meadows. Tolerant of moist conditions on the peripheries of ponds and streams. May be grown in containers as an annual.