My plants are suffering because my two rows of plants, that once had plenty of space in-between no longer do! Each gaillardia plant has grown to be 2 feet in diameter. The inner leaves, and most bottom leaves have wilted and turned yellow. I think this is because of the over-crowding. I am anxious to move every-other plant, to remedy this, and don't want to wait until fall. I live in zone 5, Indiana. Is there anyway to take some of these plants out without killing them off?

Please help!