This has never happened to me, but just suppose you didn’t get around to cleaning up your perennial garden this fall. You look out the window at a raw and drizzly day and realize your gardening get-up-and-go got up and went. Don’t beat yourself up. Horticultural thought leaders think you’re doing exactly the right thing by staying out of the garden until next year.
Used to be it was a mark of gardening good citizenship to cut back perennials and remove the debris from the garden at the end of each growing season. That’s still the recommendation for vegetable gardens. As interest in native plants (and the wildlife that’s linked to them) and sustainable gardening have grown, and as our knowledge of perennial gardening has expanded, ideas about what constitutes wise landscape management have changed, too.
Turns out, leaving perennial seed heads and foliage standing provides important food sources for birds as well as good overwintering places for many beneficial insects. The foliage also helps insulate and protect the crowns — the growing points — of perennials by trapping leaves and snow around them. What’s more, frost-etched or snow-tipped seed heads and foliage can be quite decorative during those months when there’s not much else of interest in the landscape.
There are some things, however, that are worth cleaning up before winter begins. Ideally, it’s best to remove foliage that’s diseased. Peony foliage, for instance, is highly susceptible to peony blotch (red spots), botrytis blight (gray mold) and powdery mildew. Phlox and bee balm are also prone to powdery mildew. Black-eyed Susan foliage is often covered with black circles of septoria leaf spot. After all the rain this growing season, you may find more than the usual amount of diseased foliage. All this foliage should be cut back and thrown away — not composted or left on the ground. This helps prevent the fungal spores of these diseases from lying in wait in the soil to infect plants next year.
Another reason to do some cutting back this fall is to get ahead of vigorous reseeders like coneflower and black-eyed Susan. Although they provide nice winter interest, they also are planning to take over the world. You can cut back some or all of the stems before they go to seed to avoid having them crowd everything else out next year. If you can’t quite motivate yourself to do that now, think of it this way: You’ll just have more plants to share next year.
Although I’m a rabid gardener, by this time of year, I’d rather sit inside with a mug of tea and read a book. Now that I know all the advantages of leaving my perennials standing, I don’t let them guilt me. Instead, I look forward to that warm and sunny day in March when it will be too early to begin gardening in earnest. I’ll soothe my hankering to be in the garden by doing the cleanup that seemed so odious in November. And that, my friends, will be bliss.
Patrice Peltier lives in Spring Green and writes regularly for Wisconsin Gardening, Chicagoland Gardening and The Landscape Contractor magazines. Her work has appeared in Better Homes and Gardens and Midwest Living magazines.