Description

Commonly referred to as 'mulch volcanoes', excessive soil and mulching of newly installed and established trees is a common problem that can be easily recognized throughout many commercial and residential sites. Too thick a layer on the root zone or against the trunk can function as a habitat for pests and pathogens while creating unfavorable growing conditions.

Symptoms & Diagnosis

Trees with excessive mulch or soil will experience a loss of vigor due to a lack of oxygen and water available to the root zone. Bark and trunk rot will develop if these conditions persist. The probability of secondary infections from borers or rotting will be higher. Roots will seek out oxygen and water and will consequently begin to grow towards the surface and around trunks.

Treatment

Removing excessive soil and mulch to levels below the plants root flare will alleviate symptoms. As a general rule, mulch should not exceed a thickness of three inches and should remain off the trunk. If compaction has occurred, aeration will improve soil conditions for root growth. Any girdling or wayward roots should be pruned out.

Management

Managing plant stress is a crucial component of management. Plants can remain healthier and aesthetically pleasing longer by properly managing water, avoiding compaction and grade changes, and controlling disease. Fertilization improves tree vigor.

Affected Species

• All landscape plants