It's a warm spring afternoon, and a huge, shiny black bee is hovering by your patio cover like it owns the place. Then you notice a perfectly round hole in the wood and a little pile of sawdust underneath. Odds are you've met a carpenter bee.
Short answer: Carpenter bees are large, solitary native bees that bore round, half-inch holes into bare, unpainted wood such as redwood and cedar to raise their young. The damage is usually minor. You can stop them without killing them by painting or varnishing exposed wood, using hardwoods or non-wood materials, and plugging empty holes.
Which carpenter bees live in Southern California?
California has three carpenter bee species, according to the late UC Davis bee expert Robbin Thorp, writing for the UC Davis bee biology program. All three show up in parts of Southern California:
- Valley carpenter bee (Xylocopa varipuncta): The big one, about the size of a queen bumble bee. Females are all black with dark wings that flash violet in the sun. Males look completely different: fuzzy, golden or buff-colored, with green eyes. Lots of people don't realize they're the same species.
- Xylocopa californica: Nearly as large, with a bluish metallic sheen. It's found in the foothills around the Central Valley and in Southern California's Transverse Ranges, including the Los Angeles area.
- Xylocopa tabaniformis orpifex: The smallest of the three, though still much bigger than a honey bee. Females are black, and males have bright yellow markings on the face.
Unlike honey bees, carpenter bees don't live in big colonies. Each female builds and provisions her own nest.
What are the signs of carpenter bees?
Carpenter bees leave a pretty distinctive calling card. Look for:
- Perfectly round holes about 1/2 inch across, often on the underside of eaves, fascia boards, fence rails, decks, pergolas and patio covers
- Fine sawdust piled on the ground or on surfaces below the hole
- Stains on the wood around and below the entrance
- A tunnel that turns to run along the grain of the wood just inside the entrance
- Large bees hovering near the wood, and sometimes zooming right at your face
They're especially fond of weathered, unpainted wood. UC IPM notes that they prefer sound wood without paint or bark, attack softwoods like redwood, cedar and Douglas fir, and generally avoid most hardwoods. Here in Southern California, that describes an awful lot of fences and patio covers.
How much damage do carpenter bees do?
Carpenter bees don't eat wood the way termites do. They chew out tunnels to lay their eggs in. According to the UC IPM Pest Note on carpenter bees, a typical nest tunnel is about 1/2 inch wide and 6 to 10 inches deep, divided into cells that each hold an egg and a ball of pollen.
The trouble is that bees like to reuse and enlarge old tunnels, and several bees may share an entrance. Over many years, tunnels can stretch as far as about 10 feet into a timber. UC IPM says carpenter bee damage to structures is usually minor, but heavy, repeated nesting can weaken wood. Open holes can also let moisture, wood-decay fungi and other insects get in.
So it's worth dealing with, but it's not usually a "call someone tonight" emergency.
Carpenter bees vs. bumble bees vs. honey bees
Carpenter bees often get mistaken for bumble bees, and both get confused with honey bees. Here's a quick way to tell them apart:
| Carpenter bee | Bumble bee | Honey bee | |
|---|---|---|---|
| Abdomen | Shiny, mostly bare on top | Fuzzy all over | Fuzzy, golden-brown with bands |
| Size | Large | Large | Much smaller |
| Lifestyle | Solitary | Small colonies | Large colonies of thousands |
| Nest | Tunnels bored into wood | Existing cavities, often old rodent nests | Wax honeycomb in cavities like walls, trees and boxes |
| Damage to homes | Holes in exposed wood | Rarely an issue | Comb, honey and bees inside walls, roofs and attics |
The easiest tell is the rear end. A bumble bee is hairy from head to tail. A carpenter bee's abdomen is shiny and mostly hairless on top.
Do carpenter bees sting?
Rarely. Male carpenter bees can't sting at all. They don't have a stinger. They are territorial, though, and they'll hover in your face or dive-bomb you to check you out. It's all bluff.
Females do have a stinger, but UC IPM says they sting only when provoked or handled roughly. If you're just walking by the patio, you have very little to worry about. As always, if anyone has trouble breathing or swelling of the face or throat after any sting, call 911.
How to get rid of carpenter bees without killing them
Carpenter bees are pollinators, and UC IPM says insecticides are generally not recommended for them under most conditions. Prevention is the main tool, and it works best before nesting season gets going in spring:
- Paint or varnish exposed wood. Carpenter bees prefer bare, unfinished wood. Keep exposed surfaces painted or varnished, and keep up with it. A UC Davis extension note recommends oil-based paint or polyurethane and warns that stains alone don't reliably prevent damage.
- Fill cracks and depressions in the wood, which make easy starting points.
- Plug old holes at the right time. Fill unused holes with steel wool and caulk, then repaint or varnish, but only after the adults have emerged. Wait until you're no longer seeing bees use the hole. Sealing a hole while bees are still inside just traps them.
- Cover rough areas. Wire screening or metal flashing over exposed timber ends and rough spots makes them much less inviting.
- Choose materials they don't like. For new projects or repairs, use hardwoods for exposed exterior parts where you can. Non-wood materials like aluminum and vinyl aren't damaged at all, and pressure-treated wood is another option.
If you love having pollinators around, consider leaving an old untreated stump or snag in a back corner of the garden. UC Master Gardeners suggest exactly that to support carpenter bees, as long as it's away from your house.
Is it carpenter bees, or a honey bee hive in your wall?
This is where people sometimes get mixed up, and the difference matters. Carpenter bees drill their own holes, and you'll usually see one or a few big bees at a time. Honey bees never drill. They move into an existing gap, like a crack in stucco, a gap under the roofline or a hole around a pipe, and build wax honeycomb inside the cavity.
If you're seeing a steady stream of smaller, fuzzy, golden-brown bees going in and out of one opening, or you hear a humming sound inside a wall, you're probably looking at a honey bee colony. That's a job for live bee hive removal, where the bees and all the comb come out and the bees are relocated to a local beekeeper. Painting won't fix that one. For more on honey bees around the house, see my residential bee removal page.
Need a hand?
I don't remove carpenter bees as a service. But I'm happy to come out for a free inspection, tell you whether you're dealing with carpenter bees, honey bees or something else, and give you straight advice on what to do next. If it's honey bees, I'll remove them alive with no chemicals. I help homeowners in Riverside, Claremont and all across Orange County, the Inland Empire and LA County. Call me at (626) 487-6052 or request a free quote.
