Why We Love Leaf Litter

Fall is its own kind of fun: leaves changing colors, pumpkins, apple cider and giant leaf piles to jump into. Once we’re done with our fun, sometimes we bag those leaves up and take them away. But did you know that it’s a good idea to leave the leaves? Here are some good things fallen leaves can do for nature:

1. Saving the Bees, Butterflies and Bugs: All of Iowa’s pollinators and other buggy friends need somewhere to go for winter. Flower flies — a fantastic pollinator that protects gardens against aphids — spend the winter under dead leaves, snuggled up like they found a bunch of blankets. Bumble bee queens survive the winter this way, too! Best to not disturb them. In the spring, Iowa needs its bumble bee queens to build new colonies that keep our flowers and our food growing. The black swallowtail butterfly uses leaves a little differently — these butterflies are masters of leaf camouflage. The black swallowtail butterfly spends winter in its chrysalis — the outer casing that helps them turn into a butterfly. Their chrysalis looks a lot like a dry leaf. But their disguise only works if they have leaf litter to hide in!
2. Keeping Squirrels Safe and Snuggly: When winter approaches, some of Iowa’s mammals, like squirrels, use leaf litter in their dens and nests. They stuff their homes with leaves that insulate them from the cold and make winter a little bit warmer. Some squirrels use dead leaves to make dreys, a type of nest you can see high up in the branches of trees. They look like someone stuffed a bunch of leaves between a few branches — because that’s exactly what a squirrel did! Squirrels don’t usually stay in dreys during the winter, but in the spring, they’ll want to build their dreys again. They’ll need all the leaves they can get.
3. Warming Wildflowers: Leaf litter has a special power: regulating soil temperatures. Leaves act as a barrier, protecting soil from winter weather and spring frost. Ground that isn’t insulated by leaf litter freezes much quicker. Over winter, insulating layers of leaf litter help protect seeds from the cold and from birds who might be out looking for snack. In the spring, when wildflowers and other plants begin to grow, leaf litter protects new sprouts from lingering cold and frosty mornings. Without the protection of leaf litter, brand-new, sprouting plants might freeze. With leaf litter, those brand-new plants can focus on growing!
4. Making Gardens Grow: Believe it or not, dead leaves help new things grow in the spring! Using leaf litter as mulch in gardens or flower beds keeps your gardens happy. Leaf litter helps prevent weeds from growing, keeps the soil moist and ready for planting and gives nutrients back to the soil as leaves break down. If you have to rake part of your yard, leaf mulch can be a good way to preserve leaf litter habitat. To use leaf litter as mulch, you can let the leaves that fall in your garden stay, or you can move leaf litter into the garden (very carefully, though — the garden will need those snoozing pollinators in the spring!).

Nature is all around us — even in our yards. That means we can help protect our own little patches of nature. This fall, let the leaves be (or move them to the garden bed). You’ll help all kinds of critters stay warm through winter. Once spring rolls around, your garden will bloom thanks to the pollinators you protected, the flowers you kept warm and all the nutrients your leaves gave back to the soil.