Oak Leaf Mulch for Flower Beds
Q: Can I mulch my flower beds with oak leaves?
Can I mulch my flower beds with oak leaves? Some people tell me they're too acidic.
—Robert Jacob, by e-mail
Roger Cook replies: Oak leaf mulch is great for flower beds. It's a little acidic, but a lot of plants—including rhododendron, azalea, and holly—prefer that, so I wouldn't hesitate to put it into those beds. The effect of mulch on soil pH is negligible anyway, so other flowering plants won't really mind the leaves.
However, if your soil already tends to be on the acidic side, and you don't want to make it more so, have the soil tested to determine its pH level. If the soil has a low pH and the plants in your garden prefer it to be higher, mix in some lime before you add the oak leaves as mulch. Add only enough lime to balance the soil; the lab that does the testing will give you recommendations.