CSI Horticulture Unit
July 23, 2016
In my role with MSU Extension as the Southern Gardener I’m frequently asked to evaluate problems in the landscape. There are times when I consider myself part of the CSI: Horticulture unit. Some crimes against horticulture are very obvious, such as the highly publicized crape murder spree that occurs unabated each spring. But another more insidious crime against horticulture occurs without much media attention: burying our trees alive with mulch. This is a crime of passion, because we love our trees so much. Mulching is good to reduce weeds, cool the soil, and to conserve precious water in the tree’s root zone. No matter how many times I recommend using only a 2” to 3” layer, many perpetrators insist that 6” to 10” has to be better. So the perps mulch, and mulch, and mulch. Oh the botany! A thick layer of mulch spread around the trunk of a tree encourages bark decay allowing pests, fungi, bacteria, and insects, to get under the bark and cause problems internally for the tree. Circling roots are another problem where the roots grow into the mulch instead of outward into the soil. The tree will not perform well in the landscape. Whether you use pine bark, shredded cypress or pine straw the proper way to mulch a tree is to spread an even 2” to 3” layer around the tree and pull the mulch back away from the tree trunk. Wherever there are crimes against horticulture, you can bet the Southern Gardener will be on the case. I’m horticulturist Gary Bachman and I’ll see you next time on Southern Gardening.