Aurora Tree Talk: Poor mulching techniques seenaround the city, arborist claims

by BEN ASKREN | CITY OF AURORA ARBORIST Published:

Looking around town, it seems to me many homeowners need to educate their lawn care or landscape services on the proper techniques of mulching. It is the most beneficial thing a home owner can do for the health of a young tree.

Mulches are materials placed on the soil surface to improve soil structure, oxygen levels, temperature moisture availability and weed control. Properly applied, mulch can give landscapes a handsome, well-groomed appearance but if improperly applied or if the wrong material is used, it can actually harm your trees and other landscape plants.

When should you mulch? -- annually in the spring before soil moisture decreases and temperatures increase. You should mulch prior to, during and after construction or infrastructure changes affecting tree roots or after injury to a tree.

What kind of mulch should be used? Organic materials are preferable to inorganic materials (rock, stone, shredded rubber), but when organic mulching materials decompose, they must be replenished.

I prefer these mulches: Double shredded wood chips, composted for at least a year, pine needles, leaf humus or compost.

How should mulch be applied? It should cover as much of the root system of a tree as possible, which extends past the tree canopy or drip line. Do not use more than 3 inches in depth and keep the mulch away from the base of the tree.

Piling mulch up against the trunks of trees (volcano mulching) or at depths more than 3 inches, can lead to insect and disease problems, as well as root matting and girdling. This is especially true for young trees.

By following these guidelines, your trees will be receive the benefits of conserving moisture, improving soil structure, reducing soil compaction and increasing the availability of nutrients.

Now that you have this knowledge of how to use mulch most effectively, educate your lawn care specialist so he is actually helping your trees and not slowly causing their demise.

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