A Master Gardener's Journal

Want to make a Master Gardener shudder in horror? Mention mulch volcanos—those cone-shapedl mounds of mulch applied to the base of trees. They’re everywhere. And where there are mulch volcanos, tree death can follow.

But mulch isn’t bad, it’s good—right? I’ll give a conditional yes to that question. Mulch is a great help to trees, if it’s applied correctly. Mulch helps control weeds, reduces erosion, helps water penetrate to the roots and conserves soil moisture. It looks nice, too.

However, mulch that’s too thick will suffocate plant roots and cause the soil to become water-logged, resulting in root rot or fungus disease. And mulch applied directly against the tree trunk can create constantly moist conditions that allow disease to develop.

And there's another reason to place mulch away from tree trunks. Rodents love nesting in thick mulch. It gives them secret access to gnawing on your tree bark. Did you know that tree death can be caused by rodents gnawing all the way around the trunk of a tree? You won’t realize what’s happening till it’s too late because the destruction of the bark is hidden by the mulch.

Here’s the correct way to mulch around a tree:

Apply to a depth of 2 to 3” only
Apply at least 3-4 inches away from tree trunks
Extend mulch out to the drip line.

Ok, now that you know the proper way to mulch, please help keep our precious trees alive. Join us in stamping out mulch vlocanos!

Need more information? Go to Why Volcano Mulches Are Bad or call our Master Gardeners Hortline at 610-690-2671.

Do you have a gardening question? Call our Master Gardeners hortline at 610-690-2671 on Tuesdays and Thursdays from 9 AM-12 NOON.

UPCOMING MASTER GARDENERS EVENTS

Registration required for all events (except plant sale). Please call 610-690-2655 for more information or visit our website at http://delaware.extension.psu.edu/MG/MGcalendar.