The Obedient Plant (physostegia virginiana) does like to spread, but it is easy to keep under control. It's all in the wrist. Pulling out the new shoots in the spring where they step over the line is all that it needs.
It's probably a good guess that the plant growing in my front display garden is not the best cultivar when compared to the photos found around the internet. Photos of someone else's plants show several blossoms open at the same time, as opposed to my experience of only a few.
The plant should prefer its native wet swampy soil, but it seems to be happy in full sun and the well-drained bed. It starts growing in early spring as a dense clump, providing deep green foliage for months before producing flowers at the height of summer. Heavy summer rains tend to push them over after the 2-foot high (60 cm) stalks have reached their full height at flowering time. This is a plant that doesn't shout, and can be trained despite its reputation as a bad boy.
For The Record:
Well-drained drained organic soil
Blooming: silver salvia, nicotiana, cosmos, sunflowers, canna, zinnias, basil, castor
Harvested: 5 tomatoes