Mulch: Just do it!

Mulching is one of the best practices to ensure you have healthy trees and shrubs.

One of the most beneficial practices for improving the health and growth of landscape trees and shrubs is to mulch them, especially right after planting.

Why mulch?

Proper mulching provides a variety of benefits to newly transplanted trees and shrubs. These include:

  • Soil moisture conservation
  • Moderated soil temperature variation
  • Weed suppression
  • Increased organic matter
  • Improved soil microbial activity
  • Creation of “safe zone” around trees to prevent damage from lawn mowers and string trimmers
  • Improved aesthetic appearance.

Which mulch?

A visit to a local landscape supplier or garden center will reveal a wide range of mulch choices. In general, mulches can be divided into organic mulches (those derived from ground bark, wood or other plant material) and inorganic mulches (those derived from products that will not break down, such as river rock, lava rock or recycled tires). From a plant-health perspective, organic mulches are preferred since they contribute organic matter to the soil and provide the most benefits. Inorganic mulches may be preferred for specific situations; for example use of recycled rubber products for safety around playground equipment. Research at Michigan State University and elsewhere suggests that trees and shrubs will respond similarly to most organic mulches. The most important thing is to mulch and to mulch properly. The choice between organic mulches often becomes a choice of aesthetic appearance and cost.

Common organic mulches available in Michigan include:

  • Ground or shredded pine bark
  • Ground or shredded hardwood bark
  • Ground wood chips
  • Ground pallets or wood waste
  • Ground or shredded cypress or cedar
  • Ground un-composted leaves
  • Cocoa mulch (look for pet safe mulch if used in areas with dogs).

How to mulch

  • Two to three inches of mulch is adequate – more is not better.
  • Don’t pile mulch around the base of trees (the dreaded mulch volcano).
  • Use the doughnut technique and keep a six-inch mulch-free ring around the tree base.
  • Don’t use un-composted grass clippings as mulch – they will form a thick, smelly, unsightly mat that inhibits moisture and oxygen movement to plant roots.
  • For un-composted ground leaves, use only one to two inches to reduce matting.
  • Remember, most ground pine and hardwood products are produced locally and help support Michigan’s forest products industry.

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