What is the correct way to spread mulch around a tree?
Don’t build a “mulch volcano”. This is such a common mistake that is seen in commercial landscapes and private homes. Beginning gardeners see “mulch volcanos” so much that they think that must be the correct way. WRONG!
A “mulch volcano” consists of a conical mound of bark mulch 6 to 8 inches tall that wraps around the tree trunk. Mulch should never touch the trunk and never get that deep, or a multitude of problems could result.
Instead, spread a 2 to 3 inch thick layer of whatever kind of mulch you prefer around the base of your tree, starting 1 inch from the trunk and extending out 18 to 24 inches.
Don’t apply new mulch over last year’s mulch if the resulting layer will be more than 3 inches deep. Let the old mulch decompose first.