Does landscape mulch lead to termites in your home
- Does landscape mulch lead to termites in your home?
- Mulch recommendations
- Does Mulch Draw Termites? Should I Keep It Away From My Foundation?
- The Full Answer May Surprise You
- Drainage (Moisture), Termite Control, and Your House Foundation
- Can I Mulch Around My House, or Will This Draw Termites?
- Home Termite Control Requires Diligence
- Wood Mulch And Termites – How To Treat Termites In Mulch
- Does Mulch Cause Termites?
- How to Treat Termites in Mulch
- Avoid tempting termites with your gardening practices
Does landscape mulch lead to termites in your home?
The subterranean termites found in scattered, localized areas around Iowa are routinely found in wood chip mulch and other wood products on or in the soil (lumber scraps, boards, firewood, pallets, etc.). Does this mean, as some pest control advertisements claim, that mulch attracts termites to your home or that the mulch somehow causes termites? The answer to both questions is, “no.”
Landscape mulches contribute to a stable moist environment that is good for our trees and shrubs, and unfortunately, also good for termites and other insects. Termites in Iowa live underground in large, social colonies. Worker termites come to the soil surface (or higher) to feed on wood and other cellulose materials and carry it back to share with other colony members. Termites constantly explore for food by excavating a network of random, pencil-sized tunnels through the soil in the area surrounding their nest. Termites may tunnel for distances of up to 300 feet from their nest site. The presence of moisture favors termite exploration, tunneling and feeding. Therefore, any landscape mulch may improve conditions for termite colonies, whether the termites consume the mulch or not.
This does not mean you should avoid use of mulch, nor does it endorse one type of mulch as preferable over another. The same conclusion was recently reported from research at the Structural IPM Program at the University of Maryland. They studied the impact of landscape mulches on termite foraging activity in the laboratory and in the field. Termites that fed on a steady diet of either eucalyptus, hardwood or pine bark mulch suffered significantly lower survivorship than did termites fed the standard laboratory control diet of white birch. This result suggests that although we routinely discover termites in wood chip mulch, it is unlikely that they feed heavily on organic wood-based mulches.
In the field, termites were detected with equal frequency beneath mulches of eucalyptus, hardwood, pine bark and pea gravel and bare, uncovered soil. Sustained activity over time was significantly higher beneath gravel mulch. The hospitable conditions beneath mulch likely accounted for the termite foraging activity. However, there is no evidence that the moist conditions attract termite foragers from the surrounding landscape. Rather, when the termites wander into a suitable habitat they are more likely to remain and feed in that area.
Keep mulch several inches away from the house foundation. Never allow mulch to cover windowsills or to contact house siding. Watch wood chip mulch for signs of activity if termites are present in your area. If you suspect termite activity contact several professional termite control services for inspections and estimates. Termite treatment is best left to professionals experienced in the various methods of termite control. Take your time. Do not be rushed or pressured into a hasty decision. Termites work slowly and your house will not be ruined overnight. Deal with reliable firms and get several inspections, opinions and estimates.
This article originally appeared in the May 4, 2001 issue, p. 48.
Does Mulch Draw Termites? Should I Keep It Away From My Foundation?
The Full Answer May Surprise You
Some readers, out of an abundance of caution regarding pest control, write in to ask if a layer of mulch applied next to a house foundation will draw termites (and therefore should be avoided). The short answer is this:
- To be on the safe side, you can leave a 1-foot-wide swath of ground mulch-free all along your foundation (and keep the ground here as dry as you can).
- Outside of this “mulch-free zone,” you may apply mulch (as people often do to suppress weeds in their foundation plantings), but limit its depth to just a few inches and inspect it vigilantly for termites.
Now that you have the short answer, let’s explore this issue in greater depth.
Drainage (Moisture), Termite Control, and Your House Foundation
When it comes to termite control, opinions vary on the degree of caution one must exercise when applying mulch near a house. But when mulching foundation plantings, you should, at the very least, be aware of termite issues, especially if:
- Termites are known to be a concern in your area.
- You, yourself have had trouble with termite pests in the past.
The very word, “termites” is enough to make one shudder, and with good reason. That is why it may be best to play it safe and err on the side of caution when mulching near your home’s foundation.
Drainage and termite control are two matters to keep on the front burner when applying mulch to a foundation planting. Ensuring adequate drainage is relatively simple: Grade the ground underneath so that it has about a 5-percent slope away from the house, to channel water away from the foundation. But termite-control recommendations are more complex.
Can I Mulch Around My House, or Will This Draw Termites?
Consider the various sub-questions implied when we ask such a question:
- Should the mulch be allowed to come into contact with the foundation?
- If so,
- How deep a layer of mulch is acceptable?
- And how close should the mulch be allowed to come to a wooden surface?
- Are some types of mulch preferable when it comes to termite control? Does a wood mulch actually draw these pests to a yard, in search of a snack?
Each of these termite-control questions deserves individual treatment.
There is some disagreement over the answer to the first question above. Some advise against letting the mulch come into contact with the foundation at all (you certainly should not allow such contact if a termiticide was applied to the soil along the foundation when your house was built). In other cases, if you want to err on the side of caution for termite control (and it is hard to fault a homeowner whose general policy is, “Better safe than sorry”), then this would be the correct answer for you. As mentioned above, simply keep your bed of mulch a foot or more away from the house (if this mulch-free zone allows you to sleep better at night, then it is a precious foot of space, indeed).
If you are going to be a bit less paranoid and will let the mulch come into contact with the foundation, then limit the depth of the layer of mulch to about two inches (in fact, even if kept further away from the house, a mulch layer in a foundation bed should not be much deeper than this, with four inches being maximum depth). But how close should the mulch be allowed to come to a wooden surface? Burnett’s Landscaping in Salem, Connecticut (U.S.) recommends “at least eight inches of exposed foundation between the top of the planting bed and the wood sill plate of the house structure.”
Finally, when it comes to the best type of mulch to use when termite control is a concern, there is a widespread misconception. Folks assume that, because termites eat wood, only wood mulches present a problem. That is a myth. There is also the separate question of whether, technically speaking, mulch actually draws termites to your land.
The issue is not termites being drawn to a property by the promise of a wood mulch that they can eat, but rather termites that are already present (in the soil) exploiting the mulch as a hiding place, using it as a launching pad to invade your house. Termites like moisture, and all mulches provide that to some degree. In fact, good moisture-retention is one of the prerequisites for the most effective mulches. Your plants enjoy this quality in a mulch, but so do the termites. And remember, even mulches that retain less moisture (such as stone mulches) still furnish pests with a place to hide. To sum up, the case is not so much that mulch draws termites to a property (they were probably there already), as it is that mulch makes life more comfortable for these pests. And placing mulch near the foundation, specifically, just invites them to rise up out of the soil and search for ways to penetrate your house’s walls. And who needs that, right?
The good news is that there are actually some kinds of wood mulch that termites dislike:
- Cedar mulch
- Mulch that comes from the heartwood of cypress
Incidentally, it is more accurate to say that termites eat cellulose than to say that they eat wood. Cellulose can be found in the cell walls of plants (not just trees). Consequently, termites give you another reason not to like them: They can damage your landscape plants.
Home Termite Control Requires Diligence
So what is a homeowner worried about termite control to do? First of all, if you do not already know, find out what the heck a termite looks like, anyway, using the termite picture above for identification. Next, be diligent and inspect the mulch in foundation plantings regularly, to determine if any termites are present. If you find any, do not procrastinate: Contact a reputable professional in the termite-control business immediately.
Wood Mulch And Termites – How To Treat Termites In Mulch
It’s a well-known fact that termites feast on wood and other substances with cellulose. If termites get into your house and are left unabated, they can wreck the structural parts of a home. Nobody wants that. Many people are concerned about termites in mulch piles. Does mulch cause termites? If so, we wonder how to treat termites in mulch.
Does Mulch Cause Termites?
You may, on occasion, see termites in mulch piles. But mulch does not cause termites. And termites don’t typically thrive in mulch piles. Termites typically pre-exist deep underground in moist environments. They tunnel through the earth to find woody food products for their food.
Mulch typically dries out enough that it is not a conducive environment for termites to build a nest. Termites in mulch piles are possible only if the pile is constantly kept very moist. A more realistic termite risk is caused by piling mulch too high up against your siding so that it provides a bridge over the termiticide treated foundation and into the house.
Large pieces of wood, boards or pressure treated railroad ties are even more conducive to hosting a termite nest than mulch piles.
How to Treat Termites in Mulch
Do not spray insecticides into your mulch. Mulch and its decomposition process are very important to the health of the soil, trees and other plants. Insecticides kill all the beneficial organisms in your soil and mulch. That is not a good thing.
It is best to maintain a low mulch buffer area from 6”-12” wide around the perimeter of your house. This will stop termite bridges. Some experts recommend no mulch at all in this buffer area while others say a 2” max mulch layer around your house is fine.
Keep this area dry. Don’t water directly in the perimeter zone of your house. Remove large wood logs, boards and railroad ties that are stored against your house for future DIY projects. Keep an eye out for termites as a matter of course. If you start to see termites regularly, call in a pest control expert to inspect the situation.
Avoid tempting termites with your gardening practices
Once they gain access to a house, termites can easily chew through solid wood, shredding it like this piece of a door.
I don’t normally write about things you need to do to take care of your house. However, there definitely are gardening activities that can affect your house and its well-being — in particular when it comes to termites. Detached buildings, such as wooden sheds or garages, may also be affected.
The next several months are a popular time for adding new beds of shrubs, ground covers and flowers, or for reworking and replanting existing beds.
When dealing with beds that are right next to your house, this work can affect your home’s termite protection. We often refer to these plantings as “foundation plantings” or “foundation beds” in gardening (so named because they are meant to hide the foundation of the home).
Beds out in the landscape away from the house are not an issue. But when landscaping foundation beds, the LSU AgCenter provides a variety of recommendations to avoid interfering with termite protection.
Houses in the New Orleans area (and across the Southeast) are protected from subterranean termite damage with chemical barrier-type soil treatments. When native subterranean termites enter a home, it is always through the soil right next to a slab, pier or attached structure.
The introduced Formosan termites generally do the same thing, but there are some exceptions that I’ll address later on.
Maintain the barrier
To protect a structure, the soil immediately next to the slab or piers is treated with a long-lasting liquid termiticide. Piers are also drilled and the termiticide injected into the inner void, and termiticides are also applied under the slabs of houses during construction.
The treated soil next to the slab or piers is generally about 4 inches wide and about 6 inches deep. The presence of this chemical in the soil forms a protective shield that prevents termites from tunneling through the soil and entering the structure.
The soil in this area should be considered sacrosanct and never disturbed or altered. It is all that stands between your house and an infestation of termites. If anything is done to this soil, the barrier is compromised and the risk of termites entering the structure is increased.
During bed preparation for foundation plantings, it is imperative not to dig into the soil within 8 to 12 inches of the slab or piers. If new soil is being added to the bed, it should be kept away from and not allowed to cover the soil within 8 to 12 inches of the slab or piers.
Either of these actions reduces or eliminates the effective barrier.
Protection when planting
When planting shrubs in beds next to the house, they should be located a minimum of 3 feet from the slab. This distance allows for growth of the shrubs over time. The shrubs benefit from the better light and air circulation that the space behind them provides.
That placement also keeps them from coming into contact with the house. Woody plants touching a structure may provide a route of entry to the structure for subterranean termites. Nor should vines be allowed to grow on structures, as they also may provide a route of entry into the structure for subterranean termites.
In addition, inspection is a key tool for managing subterranean termites. Structures should be inspected for signs of subterranean termites at least once a year. If plants are close to the structure, it may be difficult to get behind them to inspect the slab or piers. This is particularly true of plants with thorns or spines.
Mulches are an important part of gardening in beds, and provide numerous benefits. I encourage gardeners to use mulches in beds of shrubs, flowers, establishing ground covers and vegetable. However, when mulches are applied to beds next to your house and other structures, termite prevention needs to be considered.
The mulch debate
I often hear concerns that mulches can attract termites to a house and encourage infestation. This is usually not the case, although termites will feed on the cellulose that makes up plant-based mulches.
Generally, the mulches most likely to be fed upon by termites are wood products, such as wood chips. Some woods may have natural chemicals that make them less palatable to termites (such as redwood, eucalyptus and cedar), but these chemicals break down, leach out and don’t last indefinitely.
Wood mulches should not be used in beds next to the house. Bark-based mulches are less favorable to termites, but still may be eaten.
Pine straw is the most commonly used mulch that is lowest in cellulose, and it is a good choice for foundation plantings. Mulches that are not plant-based, such as rubber mulches, gravel and rocks, are, of course, not consumed by termites.
The placement of the mulch is more important than what you use. You should never apply mulch right up to the slab or piers of a house. This forms a bridge over the chemical soil treatment, allowing the termites to bypass the barrier and enter the home.
Keep mulches pulled back 8 to 12 inches to prevent this from happening. Mulches are not needed close to the structure if plants are planted the proper distance from the house.
The Formosan factor
Large trees near a house can clog gutters with large amounts of leaves (live oaks are shedding leaves now).
Clogged gutters overflow when it rains, wetting the wood of the fascia and roof of the house. Leaky gutters do the same thing.
Although native subterranean termites must enter the house from the soil, Formosan subterranean termites just need damp wood. So, if wood in your roof area stays damp, a colony can get started directly in that location — bypassing the soil barrier.
When possible, plant larger trees farther from your house and prune branches to minimize leaves in gutters. Keep your gutter clear of leaves and in good repair.
- Place gutters and grade your landscape so that water drains away from your house.
DAN GILL’S MAILBOX
My camellia bushes have clusters of three or four flower buds close together. Should I remove some of the buds so there will only be one bud of each cluster left for better flowers? Thank you.
This would generally only be done if you are entering your camellia flowers into a flower show and are competing for ribbons. In that circumstance, the desire for the largest, most perfect flowers to impress the judges is important. For the average gardener who is not necessarily after perfection, this is not needed. It is just not worth the time or effort. Remember, by disbudding, you are taking away flowers you would have been able to see and enjoy. In the typical garden, a larger quantity of flowers over a longer period is more important than individual flower perfection. The decision is up to you.
Last spring we had our backyard hydro-seeded with centipede. The guy put bermuda seed in the mix to make sure we got early growth and to keep rains from washing the centipede seed away. The problem is that almost none of the centipede came up. We now have a front yard of centipede and backyard of bermuda. We don’t like it. Can we overseed the bermuda with centipede seeds to establish a centipede lawn? Or are we stuck with bermuda? Thank you.
In this case, the bermudagrass was meant to be a “nurse grass.” Centipedegrass is a slower-growing grass, which is an advantage as it doesn’t need to be mowed quite as often. However, it makes establishment slow. Centipedegrass needs two growing seasons to properly establish and fill in when planted from seed. That’s why sometimes a grass that establishes faster and grows faster, such as bermudagrass or carpetgrass, is planted with it, called a nurse grass. It stabilizes the soil and prevents weed encroachment while the permanent grass grows and fills in.
The problem is that the nurse grass is not necessarily inclined to simply bow out and allow the desirable grass to grow. The bermudagrass seeds sprouted rapidly and quickly established and claimed the lawn. The young, slower-growing centipede seedlings could not compete and failed to establish. So, you are left with a bermuda lawn. The well-established bermudagrass owns the space. Scattering centipede seeds over the bermudagrass will do no good. Even if the seeds spout well, the seedlings have no chance against a well-established stand of bermuda. So unfortunately, no, that approach is not likely to work. The best, most reliable method I’d recommend to establish a centipede lawn in your backyard is to kill off the bermuda, removing it down to bare soil, and then to solid-sod with centipede sod.
Dan Gill is extension horticulturist with the LSU AgCenter.