Do Termites Eat Cedar Lumber? What About Cedar Mulch?


Assuming that termites don’t eat cedar, many homeowners prefer cedar mulch and cedar construction lumber. This assumption is partially correct, but you should be aware that there is some nuance to termites’ relationship with cedar wood.

Video showing termite damage to a cedar deck

Termites can eat cedar, but do they normally eat cedar?

Termites can eat cedar but they tend to stay away from it because cedar wood has resin and oil that tends to repel termites.

Some scientists have found evidence that cedar resins are toxic to the termites that decide to ingest them.

However, as with all wood and even lumber, resins and sap seep out of the wood over time.

This process is expedited when cedar is exposed to the elements. In the video below you can see termites in the stump seem unaffected by the cedar resins that are toxic to them.

Why is that? Well, you can also see by the condition of this stump that quite a bit of rot has already taken place. My guess is that the poisonous resins are no longer present in the wood and this cedar stump is obviously no longer resistant to an infestation.

Why Do Termites Avoid Cedar?

Scientists observed that cedar was not only repelling termites but also toxic to the termites who did try consuming it. Because of this cedar is a great type of wood to use for certain parts of construction projects.

Cedar is actually one of the more expensive types of lumber to use for construction which makes it impractical to use for the entire structure. Additionally, it would be nearly impossible to remove and replace some of the structural lumber with cedar since doing so would require demolishing significant portions of a house. Because of this, some termiticide companies are attempting to develop ways to emulate the repelling capability of cedar to treat normal lumbar. As of now, no such chemical has been developed but there is an alternative chemical that is often applied to wood to achieve a similar effect.

Termites Do Eat Cedar
A few termites eating a rotten cedar tree stump (this cedar’s resins have likely worn off)

Borate Wood Treatment As Alternative To Cedar

The most common chemical used to treat lumber to make it resistant to different wood damaging insects is borate. There are several borate-based solutions on the market but the active ingredient in all of them is borate. Borate is usually applied to lumber prior to the construction by either brushing it or spraying it onto the wood. It can even be mixed in with paint and applied to the siding of a home or a wooden fence.

However, it is sometimes used after the fact as well in spot treatment procedures. In these instances, an area infested by termites is identified and the borate mixture is injected into this area through drilled holes.

Some borate companies claim that borate treatment will last the life of the wood and that it not only protects against termites but also carpenter ants, wood boring beetles, and even wood-eating fungi.

Are There Other Types of Wood Naturally Resistant To Termites?

There are other naturally termite-resistant woods that seem to naturally repel termites including redwood and cypress. However, like cedar wood, these may keep termites away but the wood itself tends to begin breaking down sooner and do not last as long as other types of wood.

What About Mulch? Is Cedar Mulch A Good Choice?

Yes, for mulch cedar is a great choice although you should still replace it as it begins to age and rot to keep termites away. Also please keep in mind that even if termites are repelled by the resins in mulch it still can be harmful if you pile too high it around your home.

Always place your mulch near your home in such a way that allows for proper drainage because termites are attracted to damp material. If your mulch is emplaced in such a way that the soil near your foundation begins to accumulate moisture you may be creating prime conditions for subterranean termites to begin building a nest underground.

Remember subterranean termites typically thrive on two things: moisture and cellulose material. The video below demonstrates this concept by showing termite mud tubes they build when leaving the ground to protect themselves from drying out.

7 thoughts on “Do Termites Eat Cedar Lumber? What About Cedar Mulch?”

    • Paul, I really appreciate you sharing that. I have heard that termites seem to resist eating pine, cedar, and other evergreen trees, particularly when they are living. However, once such wood decomposes to the point where the sap is not as plentiful they have been observed munching on evergreens. But as you said, since the heart of pine wood has the majority of sap, they will tend to stay away from that.

  1. Hi. I was thinking of buying “Best Ever” scorpion repellant products, which is essentially concentrated cedar oil infused products, from what I understand. Some of their products such as the granules and mulches are recommended for around your house foundation and there is a spray that goes in the attic. I was concerned that I could be trading scorpions for termites. While researching, I found this site regarding termites. So, could I be drawing termites toward my foundation if I use some of these cedar products that are wood based? Your site says they are repelled by cedar but not after the oil fades.

    • Hi Katrina, great question and thanks for letting me know about the “Best Ever” scorpion repellant. I had never heard of it and the concept sounds great, many insects are repelled by Cedar resins. As far as the mulches, I would not use them because once the resin fades away, the mulch is attractive to termites. The cellulose is what the termites eat (which is in all types of wood or mulch) and if the resin fades away the termites will be attracted to it.

      However, I think the spray would not harm anything and may even help repel termites for a little while. I would guess the rain would eventually lessen the utility of this cedar based spray for termites though. This is why termites are typically tackled with a “termite trench” where a liquid is mixed in with soil around your home, essentially creating a “wall” or “barrier” within the soil around your foundation that subterranean termites cannot penetrate until the chemical wall breaks down. Which does eventually happen but can be fixed with a reapplication. These can last 5 – 10 years depending on the chemicals used. As far as repelling scorpions, I would say the spray could be worth a try. It may work well to keep other insects away too, but as I said, I’m not sure how long it would last before needing reapplication.

  2. If you re uncertain about the products available at your local lumber yard, ask before you buy make sure the type of lumber you’re getting has a good chance of standing up against termites.

  3. It’s interesting to learn that cedar lumber has resin and oil that tends to repel termites which can even be toxic to them when ingested as your article mentioned. That sounds wonderful as a wood that would be able to prevent termites and even kill them is always perfect for my home building project. I would be sure to find some supplier of cedar lumber to have a look at the material before acquiring them. Thanks!

    • Hi Jeremy, thanks for the tip about consulting a lumber supplier about the quality of various termite resistant lumber. I’m guessing that not all cedar may be equally termite resistant based upon your comment? Perhaps aged cedar may contain less of the resin and oils that repel termites? If you could elaborate that would be great!


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