Mulch is any material spread over soil as a covering. Often, mulch used in landscaping around trees is made from bark chips and is used to inhibit weed growth, hold in soil moisture, and creates aesthetic appeal. Mulch is a excellent part of any landscaping plan, but many people don’t realize that they can kill their trees with too much mulch.
Over-mulching can create a waterlogged soil and root zone, resulting in root suffocation. Roots need to take in oxygen, unlike leaves that give off oxygen. The problems that are caused from yearly over-mulching are not immediate and symptoms can take up to three to five years to show. When oxygen levels drop below 10 percent, root growth declines. Unfortunately, by the time you recognize the symptoms (off-color foliage, abnormally small leaves, poor growth and die-back of older branches), it's usually too late to apply corrective measures and the plant has begun an irreversible decline. Sugar Maple, Beech, Dogwood, Oak, Tulip, Spruce and Pine trees are most easily damaged by excessive mulch or grade changes.
Follow these tips to avoid and correct over-mulching:
- Never add significant amounts of soil or mulch around tree trunks
- Follow the rule of thumb of keeping mulch and soil below the area of the trunk flare (the trunk spread at the base of tree).
- If your trees are already over-mulched, help them ‘breathe’ by lowering the depth of the mulch below the root flare.
For more information on tree mulching, please give us a call at 877-308-8733 or request a free consultation.