Here's a link that should be helpful. The active ingredient necesary is Imidicloprid. I use the granular form made by Bayer, just spread it around, but not on the rhizomes, then water, or let the rain do its trick.. I get it at the Farm and Fleet store, but I'd guess any garden supply or farm supply store would have it. It seems to be pet safe, but one side problem is that it may be harmful to bees. It doesn't seem to harm the Japanese beetles though. (AAARRRGGGGG) Areas in the far South may not have this problem though, I hear.
http://www.irisgarden.org/bore...
