Here's my 2 cents worth. I don't divide in the fall for the simple reason that we get very strong northerly winds in winter and we lose plants if they are not well enough established - sometimes we lose them anyway! I also leave the stalks etc. on them to help trap the snow and help insulate the plant for the winter. I stake plants because of the winds and also cage them because of the rabbit population. I don't mulch in the fall because mulch provides a good home for pests. I did plant 2 evergreens in front of the house this year. They are only 4' and I intend wrap them in burlap, again because of the winds. Hope this gives you some idea. Marg

Here in zone 4, I don't do any dividing in the fall and any new planting is completed by early September at the latest. It's just too risky getting something established before winter hits.

Many people do things differently - and it's just what works for you. I cut most of my blooming perennials back in the fall. Simply because I want to get it all onto the compost pile to start its process over the winter; and because I don't like mucking around on wet soil in the spring clearing away dead debris from around emerging new growth. And I have a large yard with many garden areas and leaving clean up to the following spring would really set me back.

It's rare that we don't get adequate snow cover - and that is the best insulation against wind dessication, sun scald, thaw & freeze cycles, etc. I'm on Lake Superior and the beneficiary of lake effect snows. And we do get sustained periods of -20 during the day and -30's at night with windchills of -50. I haven't lost a perennial since the winter maybe 5-6 years ago when we had extreme cold and no snow.

I'm going to cage and burlap some new evergreens and dwarf shrubs, like marric, just because they're relatively small and would be easy targets for nibbling wildlife.

I know a lot of people pile leaves on their gardens, but I also have lots of maples and they tend to clump and form a heavy, dense, solidly frozen mat when piled up. Leaves are a compost pile item for me. I'm more afraid of things rotting under a layer of leaves that I didn't remove quickly enough than I am of the winter temps. Burlap could also have a smothering effect if laid over things.