Perennials: Butterfly Milkweed, 1 by Weerobin

Weerobin wrote:
I have always loved asclepias tuberosa.
It's always nice to have plants which thrive in poor soil.

My experience w/ a. tuberosa was so good, I wanted to try some other species.
Unfortunately, I found asclepias speciosa to be too aggressive in my garden.
I'm still pulling out runners.
The experience has made me a little gun-shy trying other species.
Are there other species which bloom nicely, but won't take over my garden?