Is Deep Root Soil Injection desirable for mature Maple trees?

Asked April 1, 2019, 4:22 PM EDT

An Arborist recommended that my mature Red and Silver Maple trees be treated with "Deep Root Soil Injection" for $300. The same arborist recently trimmed the trees for the first time in 5 years. The trees complete with grass for light, water, and food. Is this significantly better than surface fertilization of granules?

Oakland County Michigan forestry

1 Response

the first question for me is do they need to be fertilized? Are they in good health and growing well? If trees appear healthy, have good leaf color, leaves are full size, and new growth at ends of branches is four to six inches per year, then they are doing fine. We fertilize when nutrients are not available or trees are under stress. I would suggest the first step is to get a soil test to see if phosphorus or potassium is low in your soil. If nutrients are already available and trees are growing well, than they are getting the nutrients they need. A soil test would also help determine which specific fertilizer should be used. Soil injections down about 4 to 6 inches will be utilized by grass and trees. Surface fertilizer can be watered into the soil but it has the disadvantage of first passing through the lawns complete root zone instead of fertilizer applied deeper in the soil. For more information on soil testing see: