Physostegia Plant Growing & Care Guide for Gardeners

Article by Dean Ravenscroft, Ph.D. - Updated 17th Oct 2023

In this Gardener's HQ guide, we'll explore cultivating Physostegia plants in your garden, indoor spaces, and other settings.

Obedient Plant, False Dragonhead: Cultivation & Garden Use

The perennial genus Physostegia consists of hardy plants that stand tall and stiff. Ranging in height from 30 cm to 1.2 m (1 to 4 feet), these captivating plants show off their blooms from mid-summer through to early autumn.

Physostegia virginiana 'Vivid'; (Obedient Plant Vivid) by F. D. Richards.

Physotegia plants carry spiky tubular shaped flowers that may be pink, purple or white.

Some common names for the species include Obedient Plant and False Dragonhead.

How to Grow Obedient Plant and other Physostegia

Obedient Plants can be grown outdoors from seed. Sow them, and lightly cover with soil at the start of spring or autumn.

It is best to sow small species about 30 to 50 cm (12 to 20 inches) apart, and to space larger Physotegia varieties at about 60 cm (2 feet).

The soil that the plants grow in should be cool, light and slightly acidic (pH 5 to7).

Physotegia species can be grown in sunny or partially sunny parts of the garden. If growing in sunny areas ensure that the soil is kept moist.

If growing in the greenhouse first, then it should take seeds from two to four weeks to germinate. Do this at a temperature of 15 to 25 degrees centigrade (59 to 77°F).

They should be started about two months in advance. Transplant into the garden just before the last frost of spring.

Caring for Obedient Plants

Obedient plants and other Physotegia are easy to look after, but unlike their name suggests they are not obedient.

They are liable to spread, so cut the roots back hard to stop them from spreading.

The soil that they grow in should be kept moist in dry periods through watering. It is also necessary to supply mulch to the plants to ensure that the soil stays cool.

At the end of the season cut the Physostegia plant back to the ground (autumn).

Common Questions

How many members does the Physotegia genus contain?

The Physotegia genus contains 12 species.

Do Physotegia members make a good garden or landscaping plant?

Yes, Physotegia are wonderful garden plants. They're cherished for their beautiful, upright clusters of tubular flowers and their adaptability to various conditions.

Which Physotegia species are most frequently grown by gardeners?

The most frequently grown species is Physotegia virginiana (Obedient Plant). Its name comes from the fact that its flowers stay in place when moved!

Are Physotegia plants fragrant?

Physotegia plants are not typically known for their fragrance, instead, their charm lies in their striking visual appeal.

What is the perfect location to grow Physotegia?

Physotegia thrive in full sun to part shade, in well-drained soil. They're quite resilient and can handle a range of garden conditions.

Is Physotegia invasive in the USA, if so in which states?

Physotegia virginiana is currently considered invasive in some parts of the northeastern United States, due to its robust spreading habit.

How do I remove Physotegia plants from my garden?

Controlling Physotegia requires persistence. Regular digging and removal of their rhizomes will eventually diminish their presence in your garden.

Summary

Physostegia, often referred to as Obedient Plant or False Dragonhead, is a genus in the Lamiaceae family. This group of perennials is valued for its interesting flower spikes and ability to attract pollinators.

Physostegia prefers full sun to partial shade and moist, well-drained soil. Spring or fall is the best time for planting. These plants are excellent for use in mixed borders, cottage gardens, or pollinator gardens due to their attractive blooms.

I hope that you enjoyed this guide on how to grow Physostegia. You may also enjoy the following Lamiaceae family growing guides: How to grow Thyme, Agapanthus africanus, Allium caeruleum, and mint plants.