Quick answer
A thin layer of leaves shredded by the mower can break down and return nutrients. A thick, wet mat blocks light, traps moisture, and can kill grass underneath, especially under large trees.
When Mulching Works
If you can still see grass through the shredded leaves after mowing, mulching them in is fine.
When to Remove
- Leaves pile up faster than you can shred them
- Wet leaves mat down over fescue in shady areas
- Leaves clog drains, gutters, or beds
Norman's Mature Trees
Neighborhoods with large shade trees often need more than one leaf visit across fall.