I have been letting the grass grow right up to my tree trunks since I have been able to trim neatly with a line trimmer. My neighbor says I may be damaging my trees. Doesn’t the bark protect the tree?
A single trimming with a line trimmer will do little damage, but repeated trimming can eventually cut completely through the bark. Bark does more than protect the inner tree. Bark contains tubes that send food produced by the leaves to the roots. Partial damage can reduce the amount of food reaching the roots, which will slow growth. As more and more tubes become damaged, growth can become completely stunted. Trees can repair and replace the damaged bark. However, if the bark is cut completely through, all the way around the trunk, roots will gradually die, followed by death of the top. When damage is severe enough to cause stunting, it is close to the point of no return.
The best solution is to create a circle without grass around each tree or group of trees and shrubs. A minimum of 4 feet diameter should be created around individual trees. This not only prevents damage from mowers and trimmers, but creates an area without competition for water and nutrients. Grass roots are fibrous and intercept much of the surface water and nutrients before they reach the tree roots. Grass plants also produce a chemical which reduces growth of nearby plants. This competition-free area can double the growth rate of young trees and shrubs.
There are several ways to keep this area weed free besides pulling or cultivating. A 2-inch layer of compost or bark mulch will prevent 95 percent of weed growth. Weed barrier fabric will prevent 100 percent. It can be covered with mulch for an attractive appearance.
