If I come upon some that are all tangled up together, I just dig up the whole mess, and break them apart and replant the best rhizomes. You can always tell the "mother" rhizome, as there will be a place where the old bloom stalk used to be, and you can eleminate them when you are replanting. That's also a good time to add some compost to the soil and mix it in before replanting. I have about a gazillion that I have to dig up and replant this year. I have two beds that have quack grass that is winning the battle, and I need to just pull everything out and start over. Not looking forward to that.
