How Much Mulch Should You Apply Beneath Trees?

You should have no more than three inches of mulch, total (new and old) and it should not be piled against the stem(s) of the tree. When you are finished mulching, the root flares of the trees should still be visible. You see overmulched trees everywhere; despite that, it is still wrong and is actually cheaper and easier to do it the right way! Over-mulching blocks water from reaching the roots and reduces air movement throughout the soil, decreasing root growth. Girdling or strangling roots are also commonly caused by excessive mulch and soil above the root flare and stem. These damaging roots cause the decline and/or death of many young trees. Before applying new mulch to an existing bed it is important to break-up the old mulch. This prevents "caking" and allows air and water to better reach the roots. If the previous year's mulch is thick enough already, breaking it up and “fluffing” it with a rake will make it look fresh again and new mulch may not be necessary. If you have had some insect or fungal problems with your trees, it is recommended that old mulch be removed completely and replaced.

By Brad Durfee
Senior Arborist
Sprigs & Twigs Tree Service

New London County, Connecticut
www.sprigsandtwigs.net
CT Licensed Arborist #S-4283