The most eye-catching plants in my garden right now are not the ruby-red mums, the heavenly blue asters or the hybrid goldenrods turning a sun-burnished yellow.
The loudest note in this autumn symphony is without question the rosy-lilac obedient plant, living up to its cultivar name — ‘Vivid.’ Also known as “false dragonhead,” Physostegia virginiana is a native species that grows wild on moist prairies and stream banks in all but eight of the lower 48 states.
Coming in white, pink and neon-bright lavender, this plant looks something like a snapdragon on steroids. Bearing slender, saw-tooth leaves of dark green, it stands some 40-odd inches tall in my yard, towering over its neighbors in the entry garden.
Physostegia (fie-so-STEEJ-ee-uh) isn't as common in gardens as it might be, possibly due to its reputation as unruly, and the proclivity of some strains to be vigorous to the point of invasiveness. So why, you ask, do they call it "obedient" plant?
This has everything to do with its blossoms and nothing to do with its habit of growth. Each individual floret on the slender spike can be positioned at will on the four-sided stem — and will stay exactly where you put it.
This places physostegia in that small category: Plants You Can Play With. Others in the group include snapdragons, which open their "jaws" to display a snaggly "tooth" when you squeeze the sides; the seed head and long stem of the common weed plantain, which can be fashioned with a twist into a peashooter; and the explosive seed capsules of the wild impatiens known as jewelweed or "touch-me-not."
The false dragonhead produces fresh flowers and gorgeous color at the end of the season, when you need it to offset the fading annuals and spent perennials. `Vivid' in particular looks exceptionally cool with white or yellow mums, and blends beautifully with gray-leafed plants like the `Hidcote' lavender that my physostegia is now using to support its long, slender stems.
The secret to controlling this plant is to deny it the permanently damp ground that would stimulate it to overly enthusiastic growth — unless you have a marshy spot that you'd like to give over to a carefree spreader. I have mine planted near the house in well-drained soil that would be dry except for my periodic watering.
I got a bucketful of this plant from a friend of a friend (Thanks, Sandy!). I must admit I was tardy about getting it into the ground until nearly the end of November and was afraid I had killed it, but the following spring it came back again with no hard feelings. Now in its third year, the clump has spread only modestly, measuring perhaps 24 inches deep and 30 across.
I haven't found my garden bed infested with underground shoots, a deal-killer for me with plants in the mint family. Nor have I felt compelled to confine this plant to permanent pot-hood, as I have done with catmints, beebalm and culinary peppermint. I should mention, however, that I am afraid to introduce the vigorous physostegia to my streambank, mostly because I have astilbes and native trout lilies down there that I should not like to see overwhelmed.
There's a lot to be said for a plant that needs little care, and like most species that bloom late in the season, false dragonhead stays neat and crisp all spring and summer as it matures. It has no serious pest or disease tendencies. Even the voracious Japanese beetle won't trouble it — nor will deer, for that matter.
Flowering in my Central New Jersey yard commences in late August and continues in a gratifying way through mid-October. Next year, I'll try to remember to cut this clump back in spring to prevent the case of the floppies that is now causing the stems to splay out. Next spring would probably be a good time to dig and separate my clump, since division every two to three years is a recommended way to keep it under control.
Although I can't imagine a peppier color than my `Vivid' rosy-lilac, physostegia also comes in white: `Summer Snow' is one cultivar and `Miss Manners,' said to spread less aggressively, is another. `Rose Queen' and `Bouquet Rose' are rose and shell pink, respectively. There's even a giant (80-inch) pink type called `Eyeful Tower' and a variegated form with leaves splashed in white.
Garden centers occasionally carry physostegia, but they wouldn't be featured in spring, since flowering is a long way off; look around this fall. Some mail order sources for plants are: Bluestone Perennials (800-852-5243 or www.bluestoneperennials.com) and Nature Hills Nursery (402-934-8116 or www.nature hills.com). Toadshade Wildflower Farm in Frenchtown also carries them – see toadshade.com or call 908-996-7500.
Seeds are a slower way to go but can be sown in fall or early spring. Get them at Prairie Moon Nursery (866-417-8156 or prairiemoon.com)or Easyliving Wildflowers (Box 522, Willow Springs, Mo., 65793, (417) 469-2611 or www.easywildflowers.com).