Adding New Mulch or Leaving it

Q: My wife and I are in disagreement. We have azaleas and each spring I have to remove the mulch and replace it with new mulch. I think we should leave the old mulch and refresh the top layer. What say you?

A: Let me flip my office sign from “Garden Consultant” to “Marriage Counselor”! If you leave mulch in place for more than a couple of years, the layer close to the ground decomposes into a layer of rich soil: a perfect place for weeds to sprout. In addition, if the rich layer should be constantly moist, a thick mat of white fungus will grow in it. If this dries, the fungal layer becomes water repellent, so any subsequent irrigation is prevented from watering the roots of your plants. Keep these points in mind when you decide whether to add more mulch or to replace it with fresh material. Now back to my usual line of work!

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