I am just wondering if there are rules to follow about cutting down last year's dead growth for perennials. I have looked in any number of gardening books and there are no instructions on whether or not to cut liatris down to the root in spring, fall, or when it has finished blooming. Ditto for Dahlias, Peonies, etc. I realize some perennials start their new growth on the old deadwood and some start again each year. It would be helpful to me as a relatively new gardener if there was a list for all perennials on how to handle them during winter and spring. Especially in Manitoba where most of our plants are covered with snow for 8 months.