Once upon a time, many gardening years ago, my fall routine for putting the garden to bed for the winter was to pull the tomatoes and leave everything else standing until spring.
Then I discovered that vegetation left over the winter became mostly mush. I began clearing the fall garden with a vengeance, knowing I could enjoy winter with the knowledge that I’d have minimal work when the weather warmed. As my gardens expanded, I became more and more focused on fall cleanup.
Now, 40 years into my gardening life, I’ve changed my habits again. I will clear some of the garden, but not all. I’ll leave parts of plants standing where once I cut them to the ground. As always, the ornamental grasses will stand tall until spring.
Like many gardeners, my decisions about putting the garden to bed have been personal, based on how much time I have for the work and what plants look interesting in winter. In recent years, I’ve added considerations about wildlife and pollinators to the list, as well as the size of the canines in the house.
This year, with the addition of a very short rescue dog with prominent eyes and a penchant for mindlessly plunging into the garden regardless of any spiky threats, I’m either cutting perennials down to ground level or leaving the stems standing 18 to 24 inches tall. Not only does this save my dense dog from damaging an eye; it aids bees and other insects that use the pulpy stems of large perennials for overwintering and later as nursery sites.
Leaving stems standing also can act as a deer deterrent, according to Minnetonka native plant and bee expert Heather Holm. And in the spring, the tall stems quickly are cloaked by new growth.
If nature had its way, we’d leave all our plants standing during winter. Holm does that in her all-native gardens, cutting back perennials in the spring and leaving the plant litter on the ground as natural mulch. Over the winter, insects find shelter in fallen leaves, and birds and small animals profit from gardens where plants are left standing.
My garden isn’t all native plants, and I cut back most of my perennials because I hate dealing with slimy plant debris in the spring. Joe-Pye weed, one of my favorite perennials, has become an aggressive self-seeder in my yard, and the fuzzy seeds adhere to everything, including fleece jackets and my dogs’ coats. So I prune the plant back, but I’m leaving the thick stems of Joe-Pye, asters, goldenrod and cup plant standing about 18 inches tall for the bees and bugs. Not only does it benefit nature, it’s kind to my back, as well.
In winter, birds like the seed heads of coneflowers, black-eyed Susan and bee balm. I leave most of my coneflowers and black-eyed Susans standing, but I cut back the bee balm. Lately that section of my garden has been infested with four-lined plant bug, a beetle that for me has graduated from an irritant to a killer of perennials like mums and globe thistle.
Bee balm is a favorite host for the overwintering bugs. So I cut that plant to the ground and make sure the debris is gone from the yard, a practice that could help reduce four-lined plant bug numbers next year.
Pull veggies, annuals
All annuals, as well as vegetables like tomatoes, should be pulled. Leaving them in the ground encourages disease next year. And any perennials with disease problems should be cut to the ground. Phlox, which is prone to powdery mildew in late summer, should be pruned back, and fallen leaves should be raked up. Iris and peonies (except for tree peonies) are best cut back in the fall.
Most clematis are left through winter, though diseased stems and leaves should be cut back now and removed from the garden. Many types can be pruned in early spring. But others, including very early spring bloomers with flowers like tiny bells, sprout on old wood and usually may need no pruning at all. Try to keep the name tags from these plants, and look online for pruning instructions.
Most shrubs should be pruned in early spring rather than now. Beware of pruning spring-blooming shrubs at any time except immediately after flowering (usually in June). Shrubs like lilacs set their buds the summer before flowering, so if you prune them now, you’re cutting off next year’s flowers.
And then there are the lovely stars of winter, the ornamental grasses. I leave them all standing, though their feathery plumes often fall apart in the new year; plants in rich soil sometimes splay to the ground instead of standing tall until spring. Those that like to collapse get a girdle of twine attached to a hidden stake to hold them upright through snow and wind.
The only grasses I cut low in fall are very early spring growers like Karl Foerster feather reed grass. Karl Foerster sprouts so early for me that I sometimes found that even when I cut it back in mid-March, I was removing new growth along with dead leaves.
There’s a scientific reason to leave grasses standing, too. Grasses that were newly planted this year are more likely to survive if cutting back is delayed until their second spring in the garden.
In the end, putting the garden to bed is as much about you as it is about plants. Even that cozy phrase, which describes tucking beloved plants away before the snow flies, hints at a ritual that is as much personal as it is practical. I try to protect plants, wildlife, pollinators and careless dogs as I clean up for the fall, knowing that I can rest over winter and dream about next year’s garden — while watching the big grasses sway in the chilly wind.
Mary Jane Smetanka is a Minneapolis freelance writer and Hennepin County Master Gardener.