December is here and so are the seasonal rains. One quirk about the Bay Area climate is that many decidous trees will hold onto their green leaves until the first heavy rain of the season. That means that while other parts of the country are seeing snow, homeowners here are seeing some of the best weeks of seasonal color on their trees and gardeners are very busy raking leaves.
Raking leaves is an important part of Integrated Pest Management of residential gardens. All those fallen leaves harbor insect pests and diseases of the trees that they fell from. When we collect the leaves and dispose of them in the municipal compost, we reduce the number of pests and diseases that can attack the trees. Many fungal diseases will re-infect the trees from spores that are released from the leaf litter in the spring. Leaf litter is great for the home compost heap but if your heap is not actively composting properly, the pests won’t be killed.