Verticillata is a common wildflower in Europe. It is winter dormant and then grows rapidly in spring. The basal growth is hairy and soft, the flowers purple. A selection made in the 1990′s called ‘Purple Rain’ is a good plant. The flowers are darker than the species. There is also a white form which is okay. The foliage is dense and about as wide as it is high, 60cm, so it suppresses weeds.
Propagation is by division in spring and summer which then grows rapidly. If you want ‘Purple Rain’ it has to be from division. Some people offer seed called ‘Purple Rain’ but it may or may not be a good colour.
Verticillata would be drought hardy enough if it never had much moisture and didn’t put on luxuriant growth which needed moisture to sustain it. Full hot sun is not its preference. I would suggest average moisture and part shade in hot areas.
Price: $7 usually available