Come spring ... Prune these perennials
By Marilyn McKinley
OSU master gardener volunteer
Some perennials don’t fare well if pruned late in the growing season. They need winter protection provided by their fallen leaves if they are to survive. There is so much to do in the garden in the fall. I am most happy to leave some work until spring. I always think by spring I’ll have more energy. As every gardener knows, that statement makes no sense at all. When spring comes, I’m overwhelmed again. Our work is never done.
Here’s a list of favorite perennials that will do best if left alone until spring.
Astilbe. Require very little maintenance. Fall cleanup may weaken this plants tolerance for cold.
Artemisia. If pruned in the fall, produces tender growth that may experience winter kill or worse damage.
Fall asters. Most bloom into late fall and will appreciate being left alone until spring.
Butterfly bush. Wait until spring when new grow appears at the base then cut back to about 8 inches.
Black-eyed Susan. Seed heads provide food for birds.
Cardinal flower. Likes it moist, but cold wet soil will kill it. Leave foliage and stems intact.
Campanula. Don’t cut back in the fall, this encourages tender new growth that may not survive winter.
Dianthus. Many will stay green during the winter, clean up in spring.
Globe thistle. Does best when pruned midseason. Let it stand during winter, as it is good food for the birds.
Hosta. There is a chance it can be damaged by spring frosts if cut back in the fall and if not mulched properly. However, I always cut mine back in fall, seems to me that hostas survive most anything.
Joe-Pye Weed. It’s a weed, it can take the winter.
Lady’s Mantle. Does not like being sheared off too often, leave it until spring.
Lamb’s Ear. Can get ugly, but just leave it for a good spring cleaning. It’s a shelter for some small wildlife.
Lavender. Sometimes difficult to over-winter in our area, mostly due to moisture. New growth is very cold sensitive. A newer cultivar, ‘Phenomenal’ seems to over-winter very well.
Hardy mums. Leave it alone, let the flowers bloom as long as possible.
Poppies. Seem to decline once blooms are gone, but a new flush of foliage needs protection from winter.
Purple coneflowers. A wonderful food source for birds. I like the way the snow looks on the stems.
Red hot poker. Cut it back a bit when blooms fade, but leave most of it standing to protect the crown.
Russian Sage. Treat it like its lavender’s cousin. When the woody section has died back prune to the ground.
Coreopsis. I think it does best when left alone for the winter.
Turtlehead. This late season bloomer likes to be left alone until spring.
For tips on caring for perennials now and throughout the year, visit http://go.osu.edu/fallcuts.