Mulch Ado About Gardening

By Robert Seay, U of A Division of Agriculture

First posted on 07-03-2009

One side effect of the winter ice storm is the abundance of chipped and shredded dead, damaged and broken tree limbs. Should you have access to this bounty, it may prove to be a benefit or an aggravation, depending on how you use it.

Shredded hardwood material is commonly used as mulch around landscaped areas, perennial vegetable and fruit plantings. As summer and utility bills remind us, any mulched area will save on the water bill while making every day a good day for plants.

Since it contains a lot of finer material from the presence of leaves, branches and twigs this type of material can degrade fairly rapidly, serving to add benefit to the soil. Because of the more rapid decomposition rate or perhaps from being blown or washed away by wind and rain, this material may require more frequent replacement than other hardwood mulch.

Two other negatives of this hardwood material come to mind based on use and observation. One is that numerous types of native plant seedlings, including poison ivy, may emerge within the mulched area. Because of the loose nature of mulch, these plants are no trouble to remove as long as you do so initially, rather than waiting a year.

The second negative is that decaying hardwood welcomes the presence of various types of fungi growth. Fortunately, these fungal growths are part of nature’s way of decomposing organic materials, just as they are within any compost system, therefore are beneficial to the soil and basically harmless as long as left alone. You may see a number of odd growths emerge above the mulch; some may appear as a standard mushroom while others seem like the spot where the dog left yesterday’s lunch. There is no practical treatment for eliminating them, nor should there be.

Hardwood mulch should only be used for surface application, which is the idea most of us have in mind. Soil incorporation of mulch or sawdust materials will usually create a temporary nitrogen shortage around plants. Keep in mind there are more suitable materials for incorporating into soils for improving both soil texture and plant nutrition.

I’ve used truckloads of shredded tree limbs and even stockpile the stuff when available, but I continue to learn to live with its negative side. Most importantly, I know to remove poison ivy seedlings from the plant beds each spring before my wife spots them. Til’ next week!