Obedient plant (Physostegia virginiana), also known as false dragonhead, is a flowering plant in the mint family that is easy to grow. True to its name, the plant's individual flowers are "obedient" and can bend in any direction. Unfortunately, this fast-growing perennial is not so obedient in the garden, where it can spread quite aggressively by rhizomes. Its other common name, false dragonhead, likely came about because of the flowers' resemblance to snapdragons.
After being sown in late fall before any snow is on the ground, obedient plant flowers begin to open in late summer, slowly blooming from the bottom of the flower stalk upward. They should remain in bloom well into fall. The long, ovate, serrated leaves are fairly nondescript during the non-flowering part of the season. Some varieties turn red in the fall. The white, pink, and lavender flowers form along spikes, in four neat vertical rows, and begin opening from the bottom up. Pollinators like bees and hummingbirds are attracted to the obedient plant, which is easy to grow from seeds and has a germination rate of nearly 100 percent.
|Botanical Name||Physostegia virginiana|
|Common Name||Obedient plant, false dragonhead|
|Mature Size||3-4 ft. tall, 2-3 ft. wide|
|Soil pH||Slightly acidic|
|Bloom Time||Summer, fall|
|Flower Color||White, pink, lavender|
|Hardiness Zones||3-10 (USDA)|
|Native Area||North America|
Obedient Plant (False Dragonhead) Care
Although obedient plants can spread throughout the garden, the individual plants tend to be clumpers. The flower stalks will bend and stay bent if moved or blown over. Large plants may require staking and mature plants will thin out in the center and can take on an open, floppy form, telling you it's time to divide them.
Obedient plant combines well with the blue flowers of the late summer garden, such as caryopteris, Russian sage, and catmint. The spiky flowers are also a nice contract with asters, sedum, and coneflowers. Because of its obedient habit, false dragonhead is a fun plant to feature in children’s gardens for the kids to play with. Flowers of the obedient plant make long-lasting cut flowers.
The biggest maintenance chore is keeping the obedient plant from rampant spreading. Although the plants pull out easily enough, they seem to pop up everywhere. If you’re tempted to wait and let them flower, be sure to get out there before they go to seed. Long-season gardeners can get a second flush of blooms by deadheading the first flowers. This will also cut down on self-seeding.
Wait until spring to cut back old foliage. Leave it on the plants to act as a protective winter mulch.
Obedient plants are happiest in full sun, but they can handle partial shade, especially during dry summers. Full sun will produce the most blossoms.
Obedient plants are easily established and very drought tolerant, forgiving plants. Although they prefer moist, slightly acidic soil (5.5 to 6.3 pH), they’ll grow just fine in average to poor soil, and spreading will be less of a problem.
Obedient plants should be watered once or twice a week once established.
Temperature and Humidity
These are tough plants, reliably hardy in USDA Hardiness Zones 3 to 10. They prefer hot, dry regions with a temperature of 60 to 80 degrees Fahrenheit.
Don’t fertilize your obedient plants, unless they show signs of nutrient deficiencies. Less fertilizer means less aggressive spreading.
Obedient Plant (False Dragonhead) Varieties
There are several beautiful varieties of obedient plant, including these:
- Physostegia virginiana "Pink Bouquet": A profuse bloomer with soft pink flowers, this is a good choice for northern gardeners. It typically grows between 2 to 3 feet tall.
- Physostegia virginiana "Summer Glow": A tall grower with deep lavender-pink flowers, this variety reaches 3 to 4 feet tall.
- Physostegia virginiana "Variegata": White edges on leaves make this variety interesting all season. It produces pink flowers and grows up to 24 inches tall.
- Physostegia virginiana "Vivid": This plant forms short, dense clumps. It yields bright purple-pink flowers and grows up to 2 feet tall.
How to Grow Obedient Plant (False Dragonhead) From Seed
Obedient plants can be started from seed, about two months before planting out or divide existing clumps in the spring. Cuttings taken from young, tender shoots also root well. If planting from seeds outdoors, plant the seeds just below the surface of the soil in groups of about two to three seeds spaced about 18 to 24 inches apart. If you're sowing the seeds in containers indoors, the planting depth will be the same. It will take about a week for seeds to germinate. Once the plants are a few inches tall, they can be transplanted to your garden a few weeks after the last frost.