Mulch is a young tree’s best friend. It holds down competing weeds or grass, retains soil, prevents soil cracking that can damage the roots, protects the tree from lawn mower damage, and helps to prevent soil compaction. The single best and easiest thing you can do for your trees is to try to duplicate the mulch that nature provides in the forest. Organic mulches such as wood chips or pine needles contribute to better soil structure and aeration as they decompose. Common mulches include bark, wood chips, decorative gravel and crushed lava; avoid limestone rock and finely textured mulches.
Many landscapers mulch incorrectly, typically creating round mounds against tree trunks, doing more harm than good. Not only is over-mulching a waste of mulch (and money), it is rapidly becoming the number one cause of death to trees and shrubs. One of the most common causes of stress by over-mulching is oxygen starvation or suffocation of the roots. The second results from piling mulch directly against the stems of trees and shrubs. This decreases the exchange of oxygen and carbon dioxide through above ground stem tissue and promotes fungal and bacterial diseases that grow and reproduce in moist environments.
Remember these simple rules:
- Allow no mulch to touch a tree’s bark or be piled higher than three inches
- Be sure the natural trunk flair is visible at the base an the natural root depth is undisturbed
- Keep mulch a minimum of three to five inches from the trunks of young trees and eight to twelve inches from mature plants.
Being aware of proper mulching techniques can prevent premature death of your landscape investment.
From the Home and School Bulletin