I discovered a bald-faced hornet’s nest in a tree in our backyard. What is the best way to get rid of it?
— Tracy Ling, Elgin
Actually, I would encourage you to leave the bald-faced hornet’s nest alone. These are beneficial insects that are good for your garden. Bald-faced hornets are mostly black with white markings that are more pronounced on their face. Many people are afraid of wasps and hornets, so their first response when they see a nest is to call an exterminator or buy some spray to remove it. We have a large bald-faced hornet’s nest attached to our house very close to a grill shown in the photo. We do not plan to have the nest removed. We use the grill regularly and our three dachshunds roam the yard with no issues. (We only wish they were better at chasing rabbits!) The entrance to the nest faces to the side so it’s easier to avoid them. We are careful not to disturb the nest, as bald-faced hornets are typically not aggressive unless they or the nest are threatened. It would have been very difficult for me as a kid growing up to resist the temptation to take a stick and disturb the nest to see what would happen (creating a potential learning experience about consequences).
The colony will die at the first hard frost, so you do not have much more time to use caution around the nest in your garden. They will not return to the nest, though a queen may overwinter in it. The colony begins in the spring from a queen that overwintered in a protected space like leaf litter, rock piles, under a tree, in a hollow tree or in spaces in walls. The queen searches for a protected location to begin building a nest in the spring. Most nests I see are well above head height in tree canopies. The queen lays eggs in newly built brood cells. Once the female workers are developed, they will build the nest and care for young as the queen continues to lay more eggs. By mid-to-late summer, the nests can grow to be very large — up to the size of a basketball or larger — and can include several hundred adult hornets. The worker hornets leave the nest to forage for food and materials to continue building the nest. There is a lot of activity around the entrance to the nest at our house during the day.
The bald-faced hornet’s nest in the canopy of a tree in your backyard should pose little risk to you, especially if it is high up. There is a greater chance of negative interactions if you have kids who play in the area who might hit the nest with a ball. I operate a gas lawnmower less than 20 feet from the nest at my house with no issues.
For more plant advice, contact the Plant Information Service at the Chicago Botanic Garden at plantinfo@chicagobotanic.org. Tim Johnson is senior director of horticulture at the Chicago Botanic Garden.