a) they are invasive
b) muskrats LOVE them for breakfast and dinner

Our pond is still a baby at 3 years. The CT just started and haven't gotten too bad, but the muskrats that moved in last fall aren't in a big hurry to leave with the Old Pond Buffet within swimming distance. I don't know if the CT were a factor in attracting the rodents, but I am working with a plan of trapping and glyphosphate to regain control of both.