Benefits of Mulching Around Trees

Introduction

Mulching is one of the simplest yet most powerful ways to improve tree health. When applied correctly, mulch protects roots, regulates temperature, retains moisture, and supports soil biology. When applied incorrectly, mulch can suffocate a tree, harbor pests, or cause rot. Understanding what mulch does—and how to use it properly—allows homeowners to make their landscapes healthier and more resilient year-round.

Why Mulching Matters

In a forest, trees are naturally surrounded by layers of decomposing organic matter. Mulch mimics this natural environment. Most urban and suburban landscapes have compacted soil, grass competition, and disruptions to the root zone—mulch helps restore balance.

Top Benefits of Mulching

1. Moisture Retention

Mulch slows evaporation and keeps the soil damp. This is especially important during Oregon’s dry summers. Trees with consistent moisture are better able to withstand drought stress.

2. Soil Temperature Regulation

Mulch insulates the soil from extreme temperatures. In winter, it keeps roots warmer. In summer, it keeps them cooler.

3. Weed & Grass Competition Reduction

Grass is one of the biggest competitors for water. Mulch eliminates that competition and gives the tree back its resources.

4. Increased Nutrient Cycling

As mulch breaks down, it adds organic matter to the soil—improving aeration, microbial activity, and nutrient availability.

5. Root Protection

Mulch cushions the root zone from:

• Foot traffic
  
  

• Lawn mowers
  
  

• Weed trimmers
  
  

This reduces accidental damage to roots and trunks.

Mulch Mistakes to Avoid

Many homeowners unknowingly harm their trees by making these common mistakes:

• Mulch volcanoes (piling mulch against the trunk)
  
  

• Using plastic under mulch
  
  

• Mulching too deep (over 4 inches)
  
  

• Using mulch with weed seeds or non-aged materials
  
  

Mulch volcanoes are especially dangerous—they trap moisture against the bark, causing rot, disease, and pest infestations.

Proper Mulch Application

• Spread mulch 2–4 inches deep
  
  

• Keep mulch 6–12 inches AWAY from the trunk
  
  

• Extend mulch out to the drip line if possible
  
  

• Use natural, organic mulch (wood chips, bark, composted material)
  
  

Live oak (Quercus Virginiana). New Orleans LA