I have two red maples in my lawn whose roots I want to cover with mounds of "river rock" (about the size of tennis balls). Any problem?

Hi there,
I would strongly advise against covering the tree roots with any type of mulch that would cause compaction. This will certainly cause problems for your trees. Sounds like a great idea, but it would be truly detrimental to the growth and life of your trees. Sorry to be the bearer of bad news... but keep on growin'

I think if you look around, you will see older landscaped areas with trees continuing to thrive under the popular rock mulch. No reason it shouldn't work for you. Certainly better for the tree, you, and your lawnmower bouncing over the roots to cut the straggly grass under it. Put down a porous weed barrier, the felt like stuff, or heavily perforated plastic. It will reduce the weed growth while allowing water down to the tree roots.

Hi again... it is true you will see this method in OLDER landscapes, but research has shown that it is best for tree roots, especially of older trees not to be compacted or covered with soil. They can however be covered in a 2 inch layer of mulch extending out over these important older tree roots. Although they are large and cumbersome they are feeder roots and are indeed important for the tree. Because I am a lover of trees and plants I always think of the plant first. The application of mulch will protect the tree roots, look great aesthetically, and also you will have less lawn to mow!