I would wait until spring, but that's based on my experience with late planted mums in general - they just don't do as well as those planted in the spring. I realize others will disagree with that.

Just make sure you give these PLENTY of room. I'm a bit frightened to think how large mine are going to be next spring if they continue to grow at the rate they did this summer. I'm fully expecting plants 4 feet across if not more.

Kevin

I was just now listening to the podcast of the Ron Wilson In the Garden show from this morning. He broadcasts out of Cincinnati Ohio and he just got done mentioning the Mammoth Mums and how hardy they are supposed to be. He also mentioned that you need to give them plenty of room.

As I said in the other thread, I have one of the My Favorite Mums that are older but in the same group of Mums as the MMs. My plant has never gotten as large as these are supposed to be, even though it has come back for 8 years and was even moved to a different house.

If it were me, I'd wait until Spring to divide any mum. It is getting a bit late to do it now. When we moved, it was the around the second week of August that my mum was dug up and moved. It never missed a beat and bloomed on time. But it's a month later now, and I'd not be moving or dividing mums.

Linda

I hadn't heard of these 'Mammoth' Mums. I just googled images of them, wondering what colors they came in and they have a variety. I enjoy mums that come back every spring. Then they look good all summer until they bloom. I'll have to see if any local nurseries have these.

Yes, usually I go by the rule to divide either dormant, or right after bloom, but with the mums, since they bloom so late, I wouldn't disturb them until early spring either.