Landscape Mulch and Bugs

Landscape Mulch and Bugs

Many people use mulch in their landscaping for both aesthetic and practical reasons. Mulch not only looks great around flower beds and in natural areas, but also can prevent weeds, keep soil moist, and regulate soil temperature.

But who else likes mulch? Pests. Learn how to select the proper mulch for your yard and how to minimize the likelihood of it becoming infested with pests using these tips.


There are two types of mulch used for landscaping: organic and inorganic. Both mulches are great for preventing weed growth and regulating the moisture and temperature of the soil. This helps keep flower beds healthy, especially during winter and summer.

Choosing which mulch to use is largely an aesthetic choice, though there are other factors to consider as well:


Organic mulch is made of natural products and can include anything from compost and grass clippings to pine straw and shredded leaves. These types of mulches can be made at home but should not include grasses that have been treated with growth agents or other chemicals. The most common type of organic mulch around homes is wood that has been chipped, ground, or shredded.

Organic mulch will decompose over time when conditions are right, adding nutrients to the underlying soil. As a result of this natural breakdown, organic mulch will have to be replaced every one to four years.


Inorganic mulch can include stones or man-made materials such as ground tires, plastic, or other non-plant materials. Inorganic mulch is usually separated from the soil layer by landscape fabric or a plastic barrier.

Because inorganic mulch does not decompose, it typically lasts much longer than organic mulch and does not amend the soil.


Though mulch is a great landscape addition, it can harbor unwanted pests. Common insects that like to make a home in mulch include millipedes, centipedes, spiders, sowbugs, earwigs, ants, and even cockroaches. Some pests can be seen crawling on top of mulch beds, while others like to burrow under the top layer. Mulch provides both food and shelter for pests, making it a desirable place to nest.


What about wood mulch and termites? Since termites are attracted to and feed on wood, should people avoid using wood chips in their landscaping? The good news is that it’s usually only a problem if a home has a current or previous termite infestation. If this is the case at your home, an inorganic mulch may be a less risky alternative.

As for rumors that mulch can transport termite colonies, the likelihood of that happening is very small. The survival rate of termites or any insect through the mulching process is too small to sustain reproductive forms. Even when termites are found in mulch, the lifespan of mulch-fed termites is not very long.

If you’re concerned about pests in bagged mulch, all you have to do is leave bags in the sun until the mulch reaches 120 degrees Fahrenheit for one or more hours. After this, any pests should be eliminated and the mulch should be safe to spread.


In addition to leaving bagged mulch in the sun to eliminate pests before installation, here are a few other ways you can reduce pest activity in your mulch:

  • Maintain a 6-inch buffer zone between organic mulch and your home’s foundation. This reduces the chance of pests coming inside your home. The gap can be left empty or filled with inorganic mulch such as gravel.
  • Only keep the mulch layer 1–3 inches deep. Anything more can cause the mulch to dry out and too much moisture to remain in the soil, leading to root rot for your plants. Dried-out organic mulch can also cause harmful fungi to grow and create water repellent conditions, making it difficult for the mulch to decompose and do its job. After installing organic mulch, spray it down with the hose to keep this fungi away.
  • Turn the mulch regularly. This process of gently raking the mulch breaks up thatch layers in which pests may be nesting, helps organic mulch decompose properly, and ensures that oxygen continuously gets through to the soil below.
  • Before adding new organic mulch to existing landscaping beds, make sure the older mulch layer won’t impede the new layer from doing its job. Remove older mulch layers if it will make the mulch layer too deep or interfere with the new mulch.

We’re here to help you enjoy your yard to the fullest. Our highly trained field experts at Joshua’s Pest Control specialize in taking care of pest problems outside to prevent unwanted critters from coming inside. Give us a call for help making your home a place you can relax in and enjoy.