The use of shredded wood mulch exists for reasons unknown to many of us. It is true and a good point that mulch does in fact control erosion in a new planting prior to roots taking hold of soil. The wood mulch does retain more moisture and insulate roots from extreme temperatures. Therefore addition of a mulch is in deed beneficial for a newly installed shrub and tree landscape. The truth is folks have been successfully growing landscapes and gardens for centuries prior to this modern innovation commonly known as shredded mulch. So mulch is put down initially to aid plants in adjusting to their new home with less setbacks and repercussions. But renewal of mulch is where problems seem to begin.

Firstly there should never be more than 3 inches of shredded wood mulch applied after installation of new plants. Some seem to think that more is better, this is not true of mulch. Exceeding 4 inches holds too much moisture and can cause plants to decline from rot and even die because soil cannot breathe or soak up warmth from sun to rid itself of excess moisture that may be present at times. Incidentally, presence of mushrooms in a lawn or planting bed is totally due to decomposing wood matter. Whether mulch mixed with soil or an old tree stump’s roots that reside beneath current lawn. Rotting wood and moisture have always caused mushrooms to grow. It is best if one is to cultivate mushrooms to plan ahead and cultivate those that are edible and cut down on grocery bill rather than those that just make a mess in landscape

"I don’t want any weeds to have to deal with."

The infamous statement uttered by millions. That is a pretty tall order to attempt to fill. Over years, I have discovered that many people believe fallacy that rock mulch over plastic or landscape cloth will render their planting free of weeds forever and ever. Covering up soil equals no weeds?

In truth this is an absolutely not possible. After fighting weeds on hundreds of acres over decades of weeks, I can assure you it is just not possible. Nothing is sure in life but weeds and taxes. It is best to Accept fact that one will have to deal with them after a while.

That plastic will begin to deteriorate and poke up through mulch looking very unsightly. Don’t try to remove it after a few years either, it will fall all apart and be partly under dirt and partly stuck in root systems of maturing shrubs. You’ll not be able to till up parts of bed for a new look without angst over rototiller being all bound up with strips of plastic and rocks wedged tightly between tines.

Landscape plastic will only delay weeds and cause another series of problems. It is commonly known that plastic repels water. That little hole left in plastic sheeting around base of your shrub or tree is not going to allow enough water to pass through to roots at all. The fuller leaf canopy, less water will drip down through to center instead majority of moisture will run off around drip line. Plastic does not breathe either and healthy roots need air along with their water for plants to be healthy and flourish.