A while ago I called myself a lazybones for not cutting back the flower gardens after they had gone by. As the weeks went on, I still didn't bother, and look at the result! The deer have been nibbling on the spent phlox and baptisia australis (false indigo) plants. So, from my laziness comes needed winter sustenance for the deer. And you know what, they'll be much easier to cut down and pull out in the spring anyway. Plus, they provide what all the gardening books call "interest" in the winter garden, and I didn't have to do a thing except leave them standing.