How to Mulch a trees

A common tree care practice is to place a layer of mulch around a newly planted tree in a landscaped area. Mulching trees with organic mulch has many advantages. The layer of organic material covering the soil helps retain moisture, because it reduces water loss from evaporation; it insulates the ground so the soil is cooler in the summer and warmer in the winter. Mulch also helps to suppress weed growth, which means less maintenance is required, reducing the chances that the tree would be wounded with a lawn mower or weed whacker. Mulching trees lessens soil compaction, reduces erosion, improves soil aeration, and supplies organic nutrients, as long as the correct type of mulch is used. Mulching around trees or trails also can delineate pathways around the tree and gives plantings a well-cared for, uniform look.


Despite the advantages, mulching trees incorrectly can cause wounds and cankers to grow on the main stem. Mice or other rodents that will damage the tree may be encouraged; and the soil pH may be affected, which can jeopardize the health of the newly planted tree. Incorrect mulching can deplete available nitrogen in the soil, and unseasoned mulch can leech out wood alcohol which can burn the tree. Old mulch can form a hard barrier that will inhibit water penetration into the soil. To prevent these drawbacks, it is very important to apply the mulch correctly at the outset, placing a uniform 2-3 inches of mulch around the tree, making sure not to pile it against the trunk. Using the correct type of mulch is also very important, especially if acid-loving trees like oaks, pines, or magnolias are present. If you are growing acid-loving plants, it is good to use mulch that has an acidic pH such as pine needles, bark, or wood chips. You should also use mulch that has been composted in an oxygen-rich environment. Fresh “green” wood chips or chips that have been stored in a deep pile may have accumulated wood alcohol, and if this leeches into the ground, it may burn your newly planted tree to the point that it withers up and dies. A layer of mulch should also be fluffed up and turned over after a year or so to prevent the formation of a hard, impenetrable cover over the surface. Good mulch is stable, economical, pH balanced, soil enriching, well-composted, and weed free.

There is a tendency to create a volcano mound of mulch around the base of a tree. Watch the following video to see why this is bad for trees.