As homeowners who take pride in our landscapes, we naturally want to do what is best for the plants that inhabit them. One piece of advice that is often repeated is not to mulch right up to the base of a shrub. In search of a deeper understanding, you may ask yourself, “Why is the mounding of mulch along the base of shrubs harmful?” There are a few important reasons why this practice is not recommended.
Will it really harm my shrubs?
The answer to this is yes, mulching right up to the base of a shrub is harmful and will eventually cause a decline in the health of the plant. Factors such as oxygen deprivation, water retention, and root growth are responsible for this being a bad practice.
Why is the mounding of mulch along the base of shrubs harmful?
Mulch is very effective at retaining water and keeping weeds down. An even layer (3” maximum) is beneficial to the main root mass of a shrub for these reasons. However, this tendency to retain water may cause problems when mulch is mounded against the base of a shrub.
Excess Water Retention-Since mulch exhibits great water retention properties, the inside of a mound of mulch may not dry out in between rain, irrigation, or other waterings. This causes a perfect environment for weakening the protective layers of bark at the base of the shrub. The base of the shrub needs to have access to oxygen, and a waterlogged mound of mulch against the base will reduce the amount that is accessible to the plant.
Disease-Many disease-causing bacteria and fungus can thrive in a moist environment. When the base of the shrub is encapsulated in this soggy mound for long enough, the protective layers of bark may die back. This will leave the plant susceptible to all of the bacteria, fungus, and insects that may have been thriving within the mound of mulch.
Excess Root Development-As stated earlier, mounding of mulch against the base of a shrub is harmful in part due to the decreased availability of oxygen. One side effect of this is the base of the shrub sending roots into the pile of mulch, seeking a proper environment for the intake of oxygen. A tell-tale sign of over mulching is a mass of these roots formed at the bottom of a shrub. What’s worse, is that when a shrub forms these roots and then the mulch-mounding practice is corrected, these roots will die off which will harm the overall health of the tree.
Avoid Killing your Shrubs and Plants
For the health of your beloved shrubs, avoid mounding mulch at all costs. Mounding of mulch along the base of shrubs is harmful to the plant, and will contribute to its decline and ultimately its death. A good rule is to leave a few inches of space between the base of the shrub and the layer of mulch. This will ensure that the base of the shrub is able to perform its duties in balancing the oxygen and moisture intake of the plant. Hiring an expert to help maintain and improve your yard can help you avoid small but lasting mistakes such as mulch mounding. If you have invested in your yard and want to be in safe hands, we can help you keep it as healthy and beautiful as possible!