Posted: 03/04/2015 at 10:13
I don't have any now, no walls at the moment. In the past I've planted them directly in the soil, with the hope that they self seed themselves. I don't think they need to be planted that deep, think their roots are quite shallow. They are lovely plants one of my neighbours has an established clump and it looks beautiful.
When you cut them back, you can be quite tough, they seem to respond well to that, maybe leave a few flowers so they can self seed