Mulching - What Not To Do

Because mulch is the decorating material of choice for gardens across the United States, many people use it, although sometimes incorrectly. This can actually damage and cause harm to the plants in your garden. 

Laying down a layer of mulch can be very beneficial to your garden and planting beds. Mulch helps suppress weeds, retain moisture and moderate the soil's temperature.

Problem - adding too much mulch to your gardens.

• When you add mulch year after year, it can actually create a layer that won't decompose and doesn't allow root growth. The soil will then become so matted with mulch that the water and nutrients will be unable to reach and penetrate the roots causing your plants to suffer.

Problem - piling mulch up around your trees.

• First, this makes the tree look bad, like it's perched on top of a volcano.
• Excessive mulch causes the tree trunk to rot, allowing bugs and insects to attack the tree.
• This also encourages a secondary root system to develop, which will cause many problems
  • Deep, primary root system begins to wither
  • When soil near the surface is dry, tree is very susceptible during droughts
  • Without strong primary roots, the tree is more likely to topple over in strong winds or a storm

Recommendation - strip off as much old mulch as you can and if you haven't recently fertilized, apply some low-nitrogen balanced fertilizer to the newly stripped beds. Top dress with one inch on new mulch. Make sure the mulch doesn't touch the trunks of trees or shrubs!

• If you start with a stripped bed, add one inch of new mulch each year and strip the bed every three years to prevent the problems we talked about above.

Check out the full article from This Old House magazine at May is for Mulching.

The complete article also offers advice on Buying and Applying your mulch.