What are likely the last of the warm, gorgeous fall days are upon us and it seems like a great time to be puttering around the garden. But this time of year is actually not a good time to be cleaning up—that is, pruning, removing leaf litter and woody debris that fell to the soil during summer, and making your yard look somewhat like a victim of a gardening magazine makeover. And please, put away that leaf blower!
Bedtime for bugs
Many creatures—birds, for example—rely on nature’s soil cover to provide a haven for the creatures they need to eat, which they find under leaf litter and downed wood (fallen twigs, branches, logs, and the like). Zooming in a bit, we might see very small organisms, such as syrphid fly larvae, depending on such detritus for a sort of blanket to help them through the cold winter. As things warm up in the springtime, some kinds of syrphid fly larvae will actually consume enormous quantities of aphids and leafhoppers that can harm our edible plants, so why risk losing them for the sake of neatness. The adults, also called “hover flies” or “flower flies” are important pollinators (like this one pictured on a late blooming white spiraea or Spiraea betulifolia var. lucida). I see quite a variety of these little guys in my garden, possibly because I prescribe a healthy dose of leaf litter on the ground in autumn.
In addition, queen bumblebees, those lovable and fascinating pollinators who will play mom for a new generation of bumblebees next year, spend the winter under leaf litter. If we disturb their slumber or blow them away, the ecosystem will suffer. And did I mention lepidoptera (butterflies and moths), which may overwinter as eggs, larvae, pupae, or adults? If we want them to grace our gardens next year, we need to leave them and their habitat alone.
Essentially, the more we clean up and work towards a neat and tidy garden, the worse off beneficial birds, bugs, and countless other life forms will be. If you tend to be a neatnik like I am, try to catch yourself every time you start moving into manicure mode and getting overly tidy—especially in the wilder parts of the yard where wildlife may visit or set up house.
Don’t cut back
Winter or early spring is the best time to prune. Fall pruning may stimulate a plant to put on new growth, which could be sensitive to low winter temperatures. It’s good to remove diseased or dying plants—especially moldy-looking annual vegetable plant—to prevent the spread of disease to next year’s kitchen garden, but in other parts of the yard it’s best to let things go until the following spring.
Leaving seed heads on noninvasive perennials like coneflower, festuca, and lupine not only provide food for birds; they provide shelter, structure, and form. On cold, frosty mornings they can be magically transformed into silvery jewels. And when viewed closely, seed heads are fascinating in their complexity.
Down at soil level, besides providing a haven for overwintering organisms, leaf litter and woody debris protects the soil, which can degrade fairly quickly from excessive rain, sunlight, and wind. In nature, soil is protected. Mimicking the way it provides shelter will help your soil stay healthy.
Even when we’re being careful, though, it’s easy to cause disturbance. Just the other day, as I was moving a small amount of leaf litter to another area, I inadvertently uncovered an overwintering queen bumblebee. I felt terrible as I watched her stumble around, obviously weak and awoken from a sound sleep. Luckily it was a warm, dry day and she finally flew off into the sunshine. But clearly the awakening had been a rude one, because just a little while later she returned and burrowed into some loose soil a few feet from where she had been. After she was safely underground I gingerly placed a couple of particularly handsome rocks several inches from her tunnel’s entrance, as well as a large maple leaf on top of the soil to remind myself where she slumbered. Hopefully nothing else will disturb her over the coming winter.