Why? Because carpenter bees are put off by wood that’s been chemically treated (which makes it more challenging to burrow into).
The strong smells of orange, lemon, lime, lemongrass, bergamot, and grapefruit are powerful enough to deter them, yet safe enough to use around your home as a natural bee repellent.
Hanging heavy wind chimes in areas where carpenter bees might nest can be effective enough to drive them elsewhere.
Once you’re sure all the bees are out, plug the hole with wood putty or a wooden dowel coated with wood glue.
Every spring they have the huge task of drilling holes and building nests, so if they can find anything to make their jobs easier, they’ll likely take it.