Like most members of the mint family, Physostegia virginiana (aka Dracocephalum virginianum), sometimes mistakenly called false dragonhead, is best described as a robust grower. It’s native from our northern borders south through Texas, Louisiana, Alabama and Georgia. It’s also one of those plants usually described by nurseries as being easy to grow. The scientific name comes from “physa” (bladder) and “stege” (a covering), referring to the inflated floral tube.
The common name — obedient plant — is well deserved. Move each blossom back and forth or up and down, and it will stay where it’s placed. Flower arrangers have long known about this oddity, and children are also amused by this seeming power over a flower. In nature, this ability allows the blossoms to face away from a storm. And because insects such as bees or bumblebees land against the wind, the flowers have the advantage for pollination. Once moved, the flowers keep their position because of friction between the flower stalk and the surrounding bracts; remove the bracts and the flowers are limp. Obedient plant overwinters as a basal rosette of willowlike leaves.
Square stems hold opposite, thick, lance-shaped leaves, irregularly but sharply toothed. Terminal spikes of usually rose-pink flowers, resembling small snapdragons, bloom atop stems that are often more than 3 feet tall. The flowers appear from midsummer into fall.
The obedient plant does well in either sunny or lightly shaded areas but is at its best with some shade and soil that’s on the dry side, or a spot in full sun where the soil is damper.
Physostegia virginiana alba is the form with white flowers, and there’s a plus when you trade pink for white: The plants are easier to control, and this variety doesn’t demand the damp soil preferred by the species. ‘Summer Snow’ is another named variety. There’s also a variegated form called ‘Variegata’ which, like the white cultivar, lacks some of the strength necessary to take over nearby land. ‘Rose Queen’ is about 2 feet high with rose-pink flowers; ‘Bouquet Rose’ grows about 3 feet tall with shell-pink flowers; ‘Rosea’ reaches 4 feet with pink flowers; ‘Pink Bouquet’ boasts rose-colored flowers; and ‘Summer Glow’ has rich rose-crimson blooms.
Because obedient plants are aggressive, moving around with creeping roots, they naturalize with ease. And if they do transgress, simply pull them up. They’re beautiful when massed in a formal border or allowed to wander in a wild garden. But because they do wander, you should plan on dividing plants every three years.
Propagation is by seed, and remember that cultivars will produce seedlings with flowers of various colors and by division in spring or late fall.
[Peter Loewer, aka The Wild Gardener, is a regular contributor to Xpress.]