You can support butterflies, moths, bees, and other desirable insects by delaying your garden cleanup until spring. Learn simple ways to encourage overwintering insects and how to time spring cleanup.
While monarchs might migrate south for the winter, the majority of native insects overwinter right here, usually hiding in plain sight. Butterflies and moths, such as swallowtails, fritillaries, and the luna moth usually overwinter in chrysalids, cleverly blending in with leaves and dead stalks in the garden and wild areas. Fireflies and native bees hide in leaf litter or create burrows underground and stay within an inch or two of the surface. Some bees utilize natural cavities, such as hollow stems from pithy plants and grasses or tunnels into dead wood created by feeding beetles to escape the cold. As gardeners, we can help our winged friends by creating safe habitat for overwintering and resisting the urge to clean out the garden too early in the season.
In the spring, wait as long as you can to clean out dead stalks and grasses in the garden, as these may be the home of overwintering invertebrates. Ideally, home gardeners should wait until it is time to mow regularly or the plum trees have stopped blooming, since it is likely that the overwintering bees have already emerged by then to take advantage of the early blossoms. If possible, it is even better to wait until apple trees are blooming, because mining and bumble bees will be first to emerge and enjoy apple blossoms here in Pennsylvania. In the fall, consider letting your plants stand as they are instead of cutting back and removing dead material. Not only will leaf litter and dried stems provide habitat for insects, but also dead seed heads can be a food source for overwintering and migrating birds.
Many invertebrates are unable to dig through the heavy wood chip mulches. Using leaf mold or compost is one alternative; another would be to mulch the first visible feet from the front of your beds, leaving the back of the beds available to nesting bees and insects to make their homes.
Our pollinators live and overwinter in the layers of leaves left behind in the fall. It provides shelter from the cold and a great habitat for their food sources as well. Raking, shredding, and blowing leaves may destroy delicate chrysalids, as well as the insects themselves. Consider leaving one area of your yard wild, or letting the leaves lie where they fall for the pollinators. For neighborhoods with a culture of precise garden beds, you might consider downloading one of the free signs from the Xerces Society to help advertise your efforts to save the bees and other pollinators.
Want to learn more? The Xerces Society for Invertebrate Conservation has additional educational resources as well as opportunities to contribute as a citizen scientist in bumble bee watches and monarch mapping. And, don’t forget to check out Penn State’s very own Center for Pollinator Research for information on how to certify your yard as pollinator-friendly!
This educational blog is a series of informative articles from the Penn State Master Gardeners volunteers plus news concerning the group and their activities. For more information, click here.