Leave the Leaves
Imagine; the last City of College Park curbside leaf pick-up of the year is about to occur and your trees still have leaves on them. Don't fret! Did you know that leaving the leaves in your yard is actually beneficial to the environment?
Wait, but how is leaving leaves scattered about my yard beneficial? Many insects, reptiles, amphibians, and mammals overwinter and thrive in the leaf litter. The decomposing leaves also return much needed nutrients to the soil and are a natural mulch for your garden and small trees. Managing fallen leaves in your yard also helps maintains water quality in local waterways and the Chesapeake Bay, and helps conserves landfill space (which reduces methane gas emissions). We'll explain how in the next few paragraphs.
Overwintering is the process by which many animals and insects pass through or wait out the frigid or icy conditions of winter. Take for instance, the Luna moth. During the winter, the Luna moth caterpillar spins a cocoon, nests, and overwinters in leaf litter to then emerge in the spring (much like other native Maryland butterflies and moths). Fireflies are another excellent example, as they spend two years in the leaf litter before pupating into adults! Once they reach adulthood, the female firefly then lays her eggs in the leaf litter to start the process all over again. Leaving leaves in your yard will help increase firefly populations, whose bioluminescence in the summer is a wonder for all. Bumble bees and other bee species can overwinter in your home leaf compost pile, and when they emerge in the spring, pollinate all the wonderful flowers, vegetables and fruit you may grow!
Insects are not alone in overwintering in leaf litter. Salamanders thrive in the moisture of the leaf litter, and larger animals like Box turtles and birds search in the leaf litter to eat nutritious insects. Five-line skinks and other lizards that make College Park home, hunt for insects in the leaf litter, which in turn help control pest populations that may consider your spring/summer garden a delicious treat!
Not sure what to do with those leaf piles? Use leaves as mulch around your trees, under your shrubs, added to your compost pile, or as a cover for your winter garden. By doing so, leaves will return important nutrients to your garden and act as a cover for soils, greatly reducing runoff into storm water systems. This is an inexpensive and environmentally friendly way to return nitrogen, phosphorus, and potassium needed for your lawn, trees, and garden to grow. An easy way to return these nutrients to your yard is to leave the last light layer of leaves on your lawn before the final mow of the season. Then, as you mow, the broken down leaves create mulch that will further break down during the winter, returning nutrients to the soil. Then in the spring, you'll need less fertilizer, which will help reduce nutrient runoff that contributes to dead zones in the Chesapeake Bay.
If you decide to rake, please place leaf piles off the street and away from storm water inlets as leaves can clog the drains, which contributes to flooding. Leaves that flow into storm drains make their way into rivers and ultimately the Anacostia Watershed and Chesapeake Bay, which contributes to eutrophication in the bay. Not to mention, but leaves that end up in the storm drains may also end up in local landfills. The National Wildlife Federation has analyzed EPA reports on landfilled material and found that leaves can account for about 13% of waste found in local landfills. Those leaves then break down anaerobically and produce methane, which is a potent greenhouse gas.
Help our native and local wildlife and plants thrive each and every year, and help reduce contaminents entering our local water systems by leaving your leaves in the garden!
From the City's Tree and Landscape Board