Summer has rapidly receded, and the autumn colors and cool nights herald the end of the growing season. You might be tempted to go clean up your gardens, but the fallen leaves and dead stalks of plants have great value to many birds, small mammals, and insects, including butterflies. And who doesn’t like butterflies? (Well, I do know one person.) Many people like the idea of attracting butterflies to their gardens and advocate protecting them, but fall cleanup can jeopardize these same butterflies. “How can that be?” you might ask. Below is a list that someone compiled and posted here about the strategies that butterflies use for overwintering:
- Fourth-stage caterpillars hibernate in rolled leaves on the ground.
- Third-stage caterpillars make a shelter from a rolled leaf tip in which to spend the winter.
- Partially-grown caterpillars hibernate at the base of the host plant.
- Overwinters as a caterpillar in seed pods of food plant.
- Overwinters as a caterpillar in silken nests below host plants on ground.
- Overwinters as an adult in the shelter of hollow trees, under bark or utilize seasonal outbuildings.
- Hibernate as adults. For protection they use hollow logs, woodpiles and loose bark.
- Overwinters as a young caterpillar in a hibernaculum (rolled leaf) on host plants.
- Caterpillars overwinter in leafy case on host plants.
- Overwinters as caterpillar in leaf tip shelter.
I found this information very interesting. We know that monarchs migrate, but other types of butterflies use a variety of methods that are dependent on leaf litter and dead plant material to survive through the winter into the next spring season. You can imagine how cleaning up all your leaves and carting them away can have a negative impact on the next year’s butterfly population, and the next year’s, and the next.
This article by the PennState Extension provides some simple guidelines for fall cleanup, and identifies which areas are reasonable to clean up (like your vegetable garden) and which to allow to naturalize through the winter. If you’re seeking to adopt more ecologically-friendly habits, please consider leaving most of your leaves and dead plants in place through the winter. Save the cleanup for spring instead – after the redbuds and dogwoods start to bloom. You’ll find that you have some additional free time during the fall too!