The Good Side of Wasps

Admit it, you hate wasps. They aggressively intrude on picnics, swarm around playground trashcans, and congregate at nectar feeders, scaring away hummingbirds. Worst of all, they can deliver a painful sting. But wasps also do a lot of good in our garden and the greater ecosystem.

Unlike bees, which feed on nectar and pollen, most wasps are aggressive predators or parasites of other invertebrates in the garden. That’s the main reason you want them around. They tirelessly stalk the garden in search of prey and control the population of pests that would otherwise damage your plants. Some wasps are even plant pollinators. Here’s how to welcome wasps to your garden:

Know your wasps

Wasps are part of the insect order Hymenoptera, which also includes bees and ants. Like their relatives, many (but not all) wasps live communally in hives and can deliver painful bites and stings.

There is a surprising diversity of wasp species, and it’s only the aggressive yellow jacket that gives its brethren a bad name. Other North American wasps include the solitary mud-dauber, which preys on black widow spiders and builds mud tubes in which it lays its eggs, and paper wasps, which construct elaborate hives out of plant fibers and saliva. Impressively large cicada-killers feed on their namesake. Braconid wasps have larvae that parasitize the living bodies of aphids, hornworms, sawflies, and other insect pests.

Don’t kill them

Because of the wasp’s bad reputation, most gardeners don’t make an effort to attract wasps, even though it’s in the best interest of their gardens. But you can easily do the next best thing, which is to avoid destroying these beneficial insects. If yellow jackets are mobbing your hummingbird feeder, get a feeder designed to exclude them. And follow the general rule of thumb for any nature-friendly garden: have a diversity of native plants. These will provide shelter, nectar, and nesting material for wasps and other beneficial insects.

Leave them alone

Hive-forming wasps tend to be the most aggressive, so avoid approaching their nests. If paper wasps or yellow jackets have a hive in your yard and it’s not near a doorway, a much-traveled path, play equipment, or any other place with frequent foot traffic, there’s little danger in leaving it there. Be aware that as the summer wanes, yellow jackets become more carnivorous, aggressive, and likely to sting. Never swat at a wasp (or bee), because you’ll only provoke it to consider you a threat.

As a last resort, remove them safely

If wasps have made their nest in a high-traffic location and removal is your only option, do it at night, when all the wasps are in the nest and inactive. You are less likely to get stung and more likely to kill the whole hive. For paper wasps, knock down the hanging nest, which should destroy it and cause the wasps to leave. For yellow jackets, which nest in holes in the ground, stick a hose into the entrance hole and run the water for a couple of hours. If you choose chemicals, use a product designed specifically for wasps and follow the instructions carefully. If you are allergic to insect stings, or if the nest is out of reach, hire a professional.

A wasp that looks like an ant

Have you ever encountered a large furry red ant feverishly scurrying through your garden? If you have, you’re the lucky observer of a unique wingless wasp that’s been misnamed the velvet ant. Adults feed primarily on nectar, but their larvae parasitize other insects. Only the females are wingless and furry. The fur protects them from getting stung as they lay their eggs on the larvae of other wasps and bees. Their vivid red coloration probably serves as a warning that they have an extremely painful sting, which has earned them their other common name: cow killer. There’s no need to kill these impressive wasps, but never try to handle them.