Spring Cleanups are finally done and we have shifted into mulch mode here at Terrapin Landscaping. In this blog post, I would like to address the proper way to mulch a tree. Mulching is one of the most beneficial practices a homeowner can use for better tree health. The benefits of proper tree mulching are as follows:
- Helps reduce soil moisture lost through evaporation.
- Helps control weed germination and growth.
- Insulates soil, protecting roots from extreme summer and winter temperatures.
- Can improve soil biology, aeration, and drainage over time.
- Can improve soil fertility as certain mulch types decompose.
- Inhibits certain plant diseases
- Reduces the likelihood of tree damage from “weed whackers” .
- Gives planting beds a uniform, manicured look.
As beneficial as mulch is, too much can be harmful. The recommended mulching depth is 2 to 4 inches. Unfortunately many landscapes are falling victim to a plague of over mulching. While organic mulches must be replenished over time, build-up can occur if reapplication outpaces decomposition or if new material is added simply to refresh color. Improper tree mulching often results in “mulch volcanoes.” “Mulch volcanoes” are excessive piles of mulch materials applied around the base of trees.
Besides being unsightly, over-mulching can cause serious problems:
- On irrigated properties, deep mulch can lead to excess moisture in the root zone, which can stress the plant and cause root rot.
- Piling mulch against the trunk or stems of plants can stress stem tissues and may lead to the development of insect and disease problems or stem girdling roots.
- Some mulches can affect soil pH and may eventually lead to nutrient deficiencies or toxic buildups.
- Mulch piled high against the trunks of young trees can cause bark rot which can girdle the trees.
- Thick blankets of mulch can become matted and may reduce the penetration of water and air.
The following are some guidelines to use when applying mulch to your trees:
- Most commonly available mulches work well in most landscapes. Some plants may benefit from the use of slightly acidifying mulch, such as pine bark. Here at terrapin Landscaping we use all natural pine bark mulch that has been aged for a minimum of 12 months.
For well-drained sites, apply a 2 to 4 inch layer of mulch (less if poorly drained). Place mulch out to the edge of a tree’s crown or beyond. Remember, if a tree had a say in the matter, its entire root system (which usually extends well beyond the drip line) would be mulched.
- If mulch is piled against the stems or tree trunks, pull it back several inches/centimeters so that the base of the trunk is exposed.
In these pictures you can see the trees in the before pictures with a clean edge and appropriate amount of mulch.