I have grown it in my garden for years and it hasen't taken over. I just
till along the row to keep it where it belongs and I crop 1/2 the row
one year and the other 1/2 the next. I replant the crowns where I just
dug them. That way I get nice big roots.
From Mel & Donnie in Bluebird Valley
http://community.webtv.net/MelKelly/TheKids