6 Myths About Wood Chip Mulch

ChipChipAfter you’ve chipped up a big pile of brush or cleaned up those fallen limbs and branches after a storm, your first thought is probably “Great!  This project is done and it’s time for a cold beer.”  Your second thought should be, “Now what am I going to do with all these nice wood chips?”  Because you don’t want to waste that stuff!  There are all kinds of ways to use wood chips around your property, but the number one thing that most people (I’m guessing) use their wood chips for is mulching gardens and flower beds.

Wood chip mulch is great for keeping the weeds down, retaining moisture, keeping soil from eroding away, and keeping your flower beds looking nice and uniform.  There are a lot of worries floating around out there, though, about bad things that wood chip mulch can do to your gardens.  According to the folks at the Puyallup Research and Extension Center at Washington State University, most of them are bunk, and wood chip mulch does much more good than harm.

Myth #1: Wood chip mulches will acidify soils.

Truth:  It makes sense that gardeners would worry about their mulches changing the pH of the soil underneath, especially if  you’ve gone to the trouble of testing the soil and making sure it has the ideal acidity.  There is no evidence, however, that wood chips mulches that sit on top of soil will change the soil’s acidity.  Some studies showed that the soil was a tiny bit more acidic right at the top where the mulch would start to decompose, but never deep enough to affect plants’ root systems.

Edge of Perennial Flower Garden with Wood Chip Mulch

Myth #2: Wood chip mulches can leach chemicals into the ground and hurt plants.

Truth:  Many plant materials do contain chemicals called allelopathic chemicals that can prevent seeds from germinating or kill small seedlings.  Most, however, have no affect on established plants, and few to no woody materials (what your mulch is made out of) contain them.  Bottom line: don’t worry about mulching established plants, and if you mulch seedlings, do a bit of research into the type of wood chips you’re using to make sure they do not contain allelopathic chemicals.

Myth #3: Mulch made from diseased trees can infect healthy trees.

Truth:  There is no evidence that mulching around a tree with wood chips made from a diseased tree will transmit disease to the healthy tree.  Do not, however, backfill the tree’s hole with wood chips, this can transmit disease.  On top of the soil, though, you’re in the clear.

Myth #4: Wood chips can be a fire hazard.

Truth:  Coarse, organic mulches such as wood chip mulches are actually the least flammable of all landscaping mulches.  Finer mulches are slightly more flammable, and rubber mulches are the most hazardous.  Learn more about what you can do to protect your property from brush fires here.

Myth #5: Wood chip mulch will cause a nitrogen deficiency in your plants.

Truth:  Studies show that wood chip mulch actually increases a broad range of nutrients in soil and plants — including nitrogen.

Myth #6: Wood chip mulch will attract termites, carpenter ants, and other pests.

Truth:  Most wood chip mulches are actually really unattractive to pests and act as a repellant.  Cedar, for example, produces thujone, which repels everything from moths and termites to ants and cockroaches.

Want to learn more about DR Chippers and Chipper/Shredders?

Order your FREE Buyer's Guide & DVD!

DR chippers Catalog Cover

What's inside

  • 24-Page Buyer's Guide
  • Action-Packed DVD
  • Money-Saving Promotions
Get My Free Buyer's Guide »