Types

• River rock and porous stones like lava rock are suitable for use around trees because these rocks allow water to drain into the soil. Smaller stones, such as pea gravel and crushed gravel, are also suitable for use around trees, but these don't provide the excellent drainage of river rock and porous stones. Generally, limestone and marble should be avoided, as these alter the pH of the soil.
  
  

Benefits

• Unlike compostable mulch, stone mulch around trees doesn't have to be replaced annually. Stone landscaping discourages the growth of grass around the tree, which minimizes the need to mow. Additionally, placing a 6-inch ring of stone around trees can help to prevent voles and mice from chewing on the bark of the tree.
  
  

Drawbacks

• Stone landscaping usually take a considerable amount of time to install, as you have to put up the border and possibly a ground cover before putting in the stones. Light-colored stones can reflect sunlight, causing the tree and any other plants around the base of the tree to warm up quickly.