How to Properly Mulch Around Tree Bases

Mulch acts as a protective blanket for your trees, suppressing weeds and retaining critical moisture during the heat of summer. When applied correctly, it mimics the natural leaf litter found on a forest floor, enriching the soil as it breaks down and providing a stable environment for delicate feeder roots. However, the common practice of piling mulch against the tree trunk—often called a mulch volcano—is a death sentence for your trees. This moisture-trapping mound invites fungal rot, encourages girdling roots, and provides an ideal hiding spot for bark-chewing rodents. Done well, your tree ring should look like a low, flat bed that respects the flare of the roots rather than burying the bark.

1. Clear bare soil first. Rake away any existing grass or debris from a three-foot radius around the tree trunk. Ensure you are working on bare soil so the mulch can make direct contact with the ground.
2. Expose the root flare. Gently brush away soil until you find the point where the tree trunk widens at the base. This root flare must remain visible and exposed to the air at all times.
3. Spread at proper depth. Apply a layer of organic mulch starting about three inches away from the trunk. Spread it outward to the drip line of the tree branches, maintaining a depth of no more than two to three inches.
4. Form the doughnut shape. Shape the mulch into a gradual slope that starts thin at the edge of the root flare and reaches your target depth a few inches out. This keeps the trunk dry while protecting the root zone.
5. Settle with gentle mist. Lightly mist the newly laid mulch with a hose to settle the fine particles. This helps the mulch knit together and prevents it from blowing away in the wind.
6. Check mulch twice yearly. Check the mulch levels twice a year to ensure it hasn't migrated toward the trunk. Rake it back if you notice it creeping inward or piling up against the bark.