Many gardeners add mulch to their flower beds and around trees for aesthetics and to combat weeds. Since there are many types of mulch, you can find the most suitable one to suit your landscape design and plants.
Mulch also benefits your plants by retaining moisture and keeping the soil warm.
But can it harm your garden? Does mulch attract bugs?
I’ll answer your questions in this article, so let’s dive in.
Mulch keeps your landscape looking tidy and neat. It also prevents the growth of weeds.
Yet, by retaining moisture, mulch can create an inviting environment for bugs and pests that might harm your plants.
Bugs prefer moist conditions, and the mulch will protect their colonies and nests under the ground. Natural mulch or organic mulch decomposes and attracts more pests than inorganic mulch.
But inorganic mulch can also create the perfect home for insects.
So, if you use mulch made of leaves, straw, bark shavings, or grass clippings, you’re more likely to see bugs in your garden.
It’s common to see cockroaches, ants, centipedes, millipedes, spiders, earwigs, sowbugs, and spiders crawling in mulch beds. They naturally seek the warmth and moisture mulch provides, so adding mulch to your garden can increase their numbers in your garden.
But not all these bugs are bad. Some of them are beneficial bugs that feed on garden pests. So, although they might bother you, they can benefit your plants in the long run as they contribute to the decomposition of organic matter and provide various animals with food.
Some of them, like ladybugs and spiders, can feed on garden pests that damage your flowers and crops.
Introducing these bugs to your garden is one of the most potent organic pest control methods. So, mulching your plants will create an inviting environment for them.
Termites cause billions of dollars worth of damage every year. They attack buildings, feeding on the wood in foundations and ceilings, and can usually lead to the collapse of buildings.
Termites cause health risks like skin irritation upon contact, and their stings lead to painful rashes. Their droppings can also cause asthma and other respiratory issues.
Some people mistakenly believe that organic mulch contains termites or can transport their colonies to their homes. This is a myth.
It’s true that termites, just like other insects and bugs, are attracted to the cool, moist environment that mulch creates. But mulch doesn’t cause their numbers to increase.
Moreover, it won’t create bridges to transport their colonies to your home. Termites won’t be able to survive the mulching and bagging processes, and there must be a high number of reproductive termites to build a large colony that represents a hazard.
Nevertheless, it’s worth mentioning that some types of mulch might appeal to certain termite species. Termites feed on wood, so if you want to avoid them, you should stay away from specific wood types.
For example, the Eastern subterranean termites prefer slash pine and loblolly pine. White birch wood is another termites’ favorite.
Certain types of ants, like carpenter ants, are attracted to decaying wood. So, if your mulch contains decomposing wood, it will be inviting for them.
Carpenter ants don’t eat wood. They usually feed on insect honeydew, insects, and plant juices.
These ants use wood to build their nests and tunnels, so you can avoid using decomposing wood in your mulch. Organic mulch also appeals to these creatures.
Using a shallow layer of mulch will disturb these bugs because they like to dig deep tunnels. They aren’t attracted to thin bark shavings because they need thick wood to dig through.
Mulch protects plants from the freezing and thawing cycle, which can harm them and affect their roots. The consistent warmth and moisture that mulch provides also appeal to several garden pests, like mice.
By adding mulch around trees and shrubs, mice find protection, so they can feed on plant roots, tubers, and bulbs without being disturbed. Thick mulch keeps mice concealed so they’re safe from predators that might wreak havoc on their nests.
Moreover, it provides warmth in the cold season, so these pests can survive the freezing temperatures.
Mice can use different types of mulch to build their nests. For example, they can use wood shavings and straw to build nests near your home.
Organic mulch from grass clippings and leaves provides mice with a food source. So, these mulch types should be avoided if you’re trying to control the number of rodents in your garden.
Although mulch can be inviting to undesirable insects and pests, nobody can deny its benefits to your plants.
Yet, if you’re dealing with a pest problem, you must think carefully about the type of mulch to use in your garden.
In general, inorganic mulch made of gravel, pebbles, plastic, or stones is less inviting to insects and bugs than organic mulch.
Aluminum-coated and clear pebbles and plastic are best at keeping pests and insects away. They reflect the sunlight and confuse these creatures, so they avoid flower beds and trees.
You can also use these mulch types to deter harmful pests, like aphids and whiteflies, that feed on your plants.
You can use cypress or cedar bark shavings if you prefer organic mulch. These wood types contain certain chemicals that repel insects and pests like carpenter ants.
Cypress heartwood mulch kills termites and can be used to control their numbers. Spreading this mulch around your garden and home will keep them away.
Some types of mulch can work to deter some pets but not others. So, while straw mulch appeals to mice, it’s pretty repelling to certain insects like cucumber beetles.
These insects can damage your crops, and they won’t be able to lay their eggs in the straw. So, spreading it around your growing plants will prevent the pests from eating them.
In addition to choosing the right type of mulch, proper application will also affect the spread of pests and bugs in your garden.
Before applying mulch that you’ve bought from the store, you can leave it in the sun for at least one day or two. The sun’s heat can kill any pests that have been bagged with the mulch, preventing their spread in your garden.
If you’re using organic mulch, you should keep at least a gap of six inches or more between the mulch and any nearby foundation. You can fill this gap with pebbles, gravel, plastic, or any other inorganic material that bugs and pests don’t prefer.
This will keep the bugs and insects contained, away from your property.
Moreover, while applying mulch around tree trunks and plant stems, leave a small gap. When it’s too close, pests and bugs will have access to food and will multiply in your garden.
You should ensure the mulch layer isn’t too deep or thick. When mulch is over three inches deep, the top layer dries out, and the bottom layer remains moist.
The extra moisture trapped above the soil creates an inviting environment that attracts many pests to your garden. This thick mulch will deprive nearby plants of oxygen and encourage the growth and spread of pathogens that cause plant diseases.
Moreover, the dry mulch won’t decompose and won’t enrich the plant with extra nutrients. If you use compact mulch, keep the layer two inches thick to avoid creating an inviting home for garden pests.
You should rake old mulch regularly to encourage the soil organisms to decompose and break it. Regular raking will also disturb pest colonies, keeping their numbers under control.
Organic mulch can be replaced every one or two years, depending on how it decomposes. Inorganic mulch needs to be rearranged to restore its aesthetic value.
Many homeowners realize mulch’s importance and its benefits to plants, shrubs, trees, and flowers. Yet, they’re also worried about pest infestations as mulch might attract insects.
Mulch creates a warm and moist environment that appeals to beneficial garden insects and annoying pests. I recommend avoiding certain mulch types if you’re dealing with a termite problem or have a carpenter ants’ infestation.
If you’re bothered by the number of insects in your garden and are worried about them traveling to your house, switching to inorganic mulch and keeping the mulch layer thin will help put them under control.
Growing up with a mom who filled her home (inside and out) with all sorts of plants, Lisa got her start in gardening at a young age. Living now on her own with a home and yard full of plants (including an indoor greenhouse), she shares all the gardening tips she’s gained over the years.