Donuts Not Volcanos

Mulch, as it naturally occurs in forests, has been described as a nutrient rich, moisture absorbent bed of decaying forest leaves, twigs, and branches, teeming with fungal, microbial, and insect life.

Trees in a natural setting aren’t covered with mulch up to their trunks. Volcano mulching, or piling mulch up against the trunk of a tree so that it looks like a telephone pole, creates a cool, damp hideaway that attracts fungus and disease. It also provides cover for mice and voles, especially in the winter when critters do the most damage. Mulch volcanos can damage or kill your tree.

Properly applied mulch should look more like a “donut” (think tree lifesaver) and be at least 2- to-6 inches away from the trunk flare. Not all trees show this distinct flare, or curve where they enter the soil. This is okay and quite natural. The trunk flare, also called the root flare, is where the first main roots attach to the trunk.

Make sure to remove any excess soil to expose the root flare. Spread the mulch to the dripline (the furthest edges of the tree’s canopy) of mature trees or at least 12” beyond the root ball for newly planted trees.

Too much mulch smothers the tree’s roots, encouraging them to grow up through the mulch in search of air. That can cause them to “girdle” or wrap around the trunk, which chokes the tree by cutting off its water supply. Two to four inches of mulch layered around the base of your tree is all you need.

Benefits of Mulching Trees

Why do we mulch?

Types of Mulch to Use & Other Tips

For trees and shrubs, organic mulch (comprised of live organisms, like wood) is best because it improves and enriches the soil as it breaks down. The most common type of organic mulch is shredded hardwood bark, with many different kinds available at your local nursery or landscape supply center.

Other, more readily available types of mulch can be great budget-savers as long as you follow some basic rules:

Leaf mulch can be a great, no-cost option as long as the leaves are finely shredded before use to ensure proper air and water flow to the soil. Leaf mulch can also be a great winter mulch for garden areas.

Grass clippings make a wonderful soil amendment because they break down quickly. Be sure to allow time for the clippings to dry out or they will be too “hot,” which can cause nutrient deficiencies and toxicity. Don’t use grass that has been treated with pesticides or herbicides.

Pine needles on the other hand, break down slowly and only need to be applied once a year. However, because pine needles acidify the soil, only spread them over acid-loving trees and plants.

Visit https://arbordayblog.org/treecare/arborist-advice-mulching-101/ for more information on mulching.