Leaves are nature’s mulch. Fall leaves provide free, organic mulch that prevents weed growth, enriches soil and provides essential winter habitat for wildlife. Leaves insulate and protect plant roots in winter and cool the soil in summer. As the leaves decompose they make an ideal fertilizer. What’s not to like? In the post-war 1960s housing boom, lumber mills had large amounts of waste bark that they needed to get rid of and the world of commercial mulch was born.The landscape industry jumped on board promoting the “clean” uniform aesthetic that is now ubiquitous in suburban landscapes. A large part of the industry is now devoted to removing leaves, the free mulch and fertilizer provided by nature, and selling us commercial mulch and fertilizer at a tidy profit.
This trend has been expensive for us and devastating to overwintering pollinators and birds. Fallen leaves sustain a universe of wildlife, providing food and habitat for birds, pollinators, small mammals, and amphibians. Without a layer of whole leaves these animals can’t survive winter and birds can’t find caterpillars to feed to their young (baby birds can only eat soft bodied insects, not seeds) in the spring.
How to Mulch with Leaves
Rake or blow a 4-inch layer of leaves in your perennial beds, under shrubs and trees, and in any other non-lawn areas of your property. After the leaves have been blown/raked into the beds, take a hose or use the sprinkler to thoroughly wet them, which will aid in compaction and keep them in place. By spring the leaf mulch will be half of its original height due to natural decomposition and your soil and plants will be enriched. If you employ a landscaper ask what would be the easiest way to leave a 4-inch leaf layer given the company’s normal routine. A great solution for excess leaves that will provide you with free compost is to construct a simple leaf corral.
Here’s a how to guide: Read more
Green Mulch
In our established pollinator gardens we do not use mulch other than a light layer of leaves because our plants act as mulch. When plants are planted closely together, their leaves shade and cool the soil and prevent weeds from establishing. There is very little room for mulch between plants after the first season. In areas under shrubs and trees we plant low growing groundcovers such as small ferns and native groundcover plants that do the work of mulch and also prevent erosion. Again, leaves are left in the fall to condition the soil and provide crucial winter habitat for wildlife.
Plant Stalks = Winter Habitat
Plants stalks provide crucial habitat for overwintering beneficial insects such as solitary bees, ladybugs, butterflies, and moths who survive winter in hollow plant stalks. Birds eat from the seed heads of standing plants. Leave your plant stalks intact until spring when temperatures have reached 50 degrees for a week straight; this is when pollinators emerge from their winter homes. Many bees will use stalks to raise their young, so we cut back hollow stalks in late spring to 18 inches rather than removing them.