They build topsoil or humus. All you have to do is use them. Sometimes leaves require special handling, such as composting or chopping, but all leaves can be recycled. The rest of this article both tests your knowledge about leaves and provides you with the latest information about reusing leaves. See how many questions you can answer correctly.
Leaves make a good mulch to mound around trees and shrubs.
Spread them about a foot thick in a flat doughnut shape as far out as you like, to under the tips of the tree branches. You can't use oak leaves on your garden because they're too acid. As oak leaves rot they lose their slight acidity, and the oak leaf mold ends up alkaline. University of Missouri Extension advisors say to test your soil and add lime if necessary to raise the pH. Foundation plantings need to have leaves raked out from under them in the spring. This practice must be a holdover from pioneer days, when everything combustible, including leaves and grass, was kept away from wooden cabins because of fire danger.