If you wait until next spring, you will have a more mature transplant that may well handle the process better than what you have now. I would wait unless you need to harvest now. Very likely both times will work, but I expect that spring will have somewhat less loss.

Thanks for the help Dutch. I was hoping that you would chime in with your experience growing such things. I was getting a little concerned since I had not seen you post recently...hope you are doing well.

I will wait until spring for the vast majority of them but I may experiment and divide a couple this fall. I don't really have anywhere to transplant them at the moment anyway as all beds are either currently occupied or spoken for by fall garlic plantings. They kind-a-sort-a went dormant for a couple months and looked pretty ragged but they are sending up a lot of new green growth now that they are dividing.

The perennial bunching onions like the tree onions and garlic chives are very forgiving about how they get handled - so much so that they can be invasive. Remember that these are true, hardy perennials. With global warming we are seeing even a lot of long day onions now surviving the winters this far north. Down by you, the whole works are even more aggressive.

Family business and a death have taken my attention over the past several weeks. Still some loose ends to tie up yet, too; so from time to time there will be gaps in my attention around here.

Thanks again Dutch! I'll try to keep them isolated and reined in.

Very sorry to hear of the death and hope that they went peacefully. Keep your chin up and post when you have time.