For years we've been told to clean up our yards in the fall. Maybe it's time to break that habit.
Butterflies, moths, bees and other beneficial insects overwinter in the landscape, so letting stems, leaves and branches stand in place can make a huge difference to their ultimate survival, Kelly Allsup, a University of Illinois Extension horticulture educator, said. Following is a new way of looking at fall "cleanup."
First: Do not remove all fallen leaves from the landscape.
"Leaves provide insulation for overwintering forms of butterflies and moths,” Allsup said.
"Also, for some species, it is extremely difficult to distinguish between a leaf and a chrysalis. Black swallowtail butterflies who dine on your dill, fennel, parsley, or carrots overwinter as a brown chrysalis that mimics an old fallen leaf. Without allowing this caterpillar to make it to adulthood, we would be without these large, shiny, black iridescent butterflies fluttering from flower to flower.”
However, allowing leaves to accumulate directly on the grass will kill it. So, clean up leaves that fall on lawns, but leave those that fall in the garden or other areas. The one caveat: If you have experienced disease or insect infestations in your garden, clean-up may be necessary to reduce future problems.
Second, stop cutting back perennial forbs (flowers).
“These plants are still hosting life, despite the browning of leaves from the frost,” Allsup said. Silvery checkerspot butterflies overwinter as caterpillars in brown skins at the base of their host plants. Black-eyed Susans, coneflower, and sunflower are host plants for these smaller orange butterflies covered in black lines, patches, and spots.
You have free articles remaining.
In addition to butterflies, carpenter and other bees nest in the pith of stems. The bees are further encouraged if gardeners cut the tips of the stems, making it easier to crawl inside.
Wait until late spring — if at all — to cut back these dead stems. Foliage will grow up around them.
If you do cut, cut back to 12-18 inches and cut the snipped foliage into large chunks and spread around the garden to prevent tossing your nesting bees into the compost pile, Allsup said.
Third, do not trim shrubs.
Fall is usually not the time to prune shrubs and large shrubs such as willow could host overwintering red-spotted purple or viceroy caterpillars. These caterpillars overwinter in a hibernaculum, a protective cone that looks like a leaf.
Fourth, do not remove downed trees and logs.
If it’s not possible to leave the entire tree, keep a few logs for bees and other insects to overwinter or nest in.
Five, do not eradicate weeds from the landscape.
Some weeds are actually very beneficial to butterflies and bees. For example, buckeye butterfly larvae feed upon the common plantain. Early-blooming weeds such as violets (violets are weeds?) and dandelions are crucial for bees in the early spring before trees flower. And blue violets are the food of the great spangled fritillary butterfly.
Caterpillars eat your plants, and butterflies and bees visit the flowers in your garden.