Mulches are materials placed over the soil surface to enhance landscape beauty, improve soil conditions, protect plants from foot traffic and lawn equipment, and suppress weeds.
Mulches can also improve soil structure and fertility. This is important in urban landscapes where soils are often compacted and lack organic matter, especially on new construction sites. Mulching mimics the natural environment found in forests where leaves and branches blanket the soil surface, replenishing nutrients as they decompose and creating an ideal environment for root growth. Urban landscape trees and shrubs typically grow in much harsher environments with soils modified by human activities (e.g., construction, lawns, and compaction). A 2- to 4-inch layer of mulch can re-create aspects of a forest’s soil environment. According to the International Society of Arboriculture, mulching, when done correctly, is one of the most beneficial practices a homeowner can do for the health of a tree or shrub.
Proper Mulching Method:
Organic mulches are preferable due to their soil-enhancing qualities. Hardwood bark makes very good, inexpensive mulch, especially when it contains a blend of bark, wood, and leaves.
Mulch can be applied to landscape trees at just about any time of the year. However, the best time to apply mulch is in the middle of spring, once soil temperatures have warmed enough for root growth to begin.
Mulch as much of the area as possible, preferably to the outermost edge of the tree’s canopy, referred to as the “drip line.” Keep in mind, the drip line moves out as the tree grows.
Apply a 2- to 4-inch layer of organic mulch and no more; use less if the soil is poorly drained. More than 4 inches may harm the tree’s root system. If using finely textured or doubleshredded mulch, use 1 to 2 inches since these materials allow less oxygen through to the root zone.
For tree health, keep all mulch material away from the trunk. Allow the root flare (where the trunk meets the soil) to show. The root flare is at or near the ground line and is identifiable as a marked swelling of the tree’s trunk where roots begin to extend outward. Click here to read more >