09/24/2026
The "leave the leaves" advice isn't about which tree they fell from. It's about where they land.
Leaves in garden beds, under shrubs, in the corners you don't mow — leave them. That's where moth pupae, firefly larvae, and overwintering butterflies actually are. Oak and beech are the best because they don't break down until spring.
Leaves on the lawn — different story. Anything thicker than an inch smothers grass by March, and thick leathery leaves like magnolia and sycamore do it fastest. Mow over them once to shred, or rake them into the beds.
Two exceptions to leaving anything: fruit tree leaves if the tree showed scab, spot, or curl this year — the spores overwinter in them. And walnut leaves near tomatoes and peppers until they've composted a month.
The leaf isn't the problem. The lawn is.