Catherine, at A Gardener in Progress asked me what kind of knautia I have, and I told her I wasn't sure, but I seem to have 2 kinds.
The bed on the left was put in when our neighbor had to have her water main replaced. The next year, we added the bed to the right of the sidewalk. Some of the plants are the same as the other side, but some, I just put in something similar. I added knautia from a friend's garden across from the other. They've been in several years now, and are a bit different from each other.
This is the one on the right, that I think looks like Catherine's:
This is the one on the left, more compact, and not blooming yet:
Do you think they look like different kinds? I'll post a photo of the smaller one when it blooms. I don't remember if there is a difference in the flowers.