Get It Growing: Paper wasps in the vegetable garden

The paper wasp (Polistinae) is a beneficial insect to have in a garden, especially a vegetable garden. It is a less aggressive species of wasp and less likely to sting humans while foraging for food.

The paper wasp hunts other insects such as caterpillars and flies. This can help reduce garden pests and prevent damage to plants, as well as reduce the need for harmful chemicals such as insecticides. The adult wasps also feed on nectar and act as pollinators, though less than many species of bees. Active from April through September, they will spend much of their time foraging for insects to feed to their larvae back at the nest.

A few nests, left undisturbed and in areas where physical contact with humans is less likely, can produce enough wasps to prey on unwanted insects in the garden. It is important to be aware of the nest sites and safely remove any that could become problematic, such as nests near doorways or seating areas.

Wasps become lethargic when the temperature is cool, so early mornings or late evenings are good times to knock down paper wasp nests that are in unwelcome locations. Removing problem nests early in the season is much easier as the numbers of individuals belonging to a nest increases as the summer goes on.

The European paper wasp is often confused with the much more aggressive yellow jacket wasp, as they are of very similar size and coloration. Two distinguishing features can help differentiate the two species. The paper wasp has orange antenna, antennae or antennas is plural while the yellow jacket usually has black. However, this requires a close look at the wasp, and may result in getting stung.

The other differentiation is that the paper wasp has longer legs that dangle down when they fly.

Paper wasps and yellow jackets are quite different in how they nest. Paper wasps live in small colonies that build open, umbrella like nests not much bigger than a few inches across. It is typical to see many of these small nests around the home and landscape. Yellow jackets, on the other hand, commonly build nests in underground cavities that are not so visible.

Another difference between the two types of wasps can be the foods that attract them. Paper wasps prefer live insects, so are not drawn to picnic foods. Yellow jackets are the ones that become pests at barbecues and outdoor gatherings.

One reason paper wasps are less likely to sting is they have fewer colony members. That means most individuals are out gathering food to care for the larvae instead of protecting the nest.

Yellow jacket colonies can have thousands of wasps; so many individuals are guarding the entrance to the nest all the time.

Paper wasps like warm, rain-protected spots for nest-building, such as the eaves on the south side of buildings. They often nest under fence rails. One method to encourage nests near a vegetable garden is to turn empty clay pots upside down in a sunny spot nearby. Paper wasps will use the exposed drainage hole of the pot for access.

Be aware that paper wasps will make their way deep into a head of lettuce or kale to scour out the caterpillars, so take care when harvesting.

Both paper wasps and yellow jacket colonies die out during the winter, with only a few queens hibernating to start brand new colonies the next spring. Neither return to the old nests, choosing to build anew every year.

All wasps serve important roles in the ecosystem, but some have distinctly bad tempers. The more benign paper wasp, however, can become a useful and acceptable helper in the vegetable garden. So next time you see a wasp with long legs and orange antennae, consider leaving a few nests in or near your yard. Your plants will thank you.

Cece Fitton has been a Master Gardener volunteer since 2017; she is on the team developing the pollinator garden at Woodcock Demonstration Garden.