Just because they sting…
Most wasps are beneficial because they eat other bugs. They are, however, more aggressive than common bees and can sting multiple times. If you disturb their nest or kill one, they release chemicals that signal the nest to attack. This is a defence mechanism, so you can’t take it personally if they come after you. We find them nesting under the tables, in pots and in the bird houses. They like places that prevent their nest from getting wet. In late summer and the fall, the wasp population is at its highest and this is when we get the most questions about them. We found wasp nests, in some strange places this fall. They seem to have a particular affinity for some weeping arborvitae, we have and a particular pyramid Ligustrum. Yesterday, one of the guys moved 2 Texas Sage about 30 feet, before we noticed the nest in it. The wasps didn’t even move off the nest (proof that they are good parents). We were more surprised that they built a nest in a plant, that offered them no protection.
They are in my tree!
A customer asked what she could do about the wasps in her tree. The answer is not as cut and dry as “kill them”. I hate to suggest that, but sometimes you just have to. On the other hand, why were they there. There are 2 scenarios that need to be looked at. The wasps are either building a nest in the tree or hunting. Deciding what you should do, hinges on what the wasps are doing.
Dinner is served
If you don’t see a nest in the plant, you can be sure they have one near by. If wasps are hunting, just let them be. They are eating something and providing you with a valuable service. The bigger question, in this situation, is what are they eating and is it eating your tree. You may have a bigger problem with the tree, than wasps. If you use weed and feed (Atrazine) the tree is stressed out and the critter the wasps are hunting, may be feeding on your tree. The wasps are just taking advantage of the situation…do not expect a thank you note for the lovely dinner party.
We’re your new neighbors
Just like people who move in next door, you might find yourself wishing the wasps would leave. If you see a nest, then you might want to spray (if only it was that easy to get rid of those bothersome neighbors). Traditional wasp sprays are oily (which is why they work so well), but can really burn the foliage of your plants. If the leaves of your plants fall off every year (a deciduous tree or plant), you could sacrifice a few of the leaves now, since they are going to fall off anyway. If your plant is evergreen and can you live with a plant that has a bad leaves on it for a while, go ahead and spray. We have used Formula 409 to kill wasps and it seems to be easier on the plants and can be rinsed off, because it isn’t oily. The down side is that the firing range isn’t as great, so you need to get closer. Wasps are more sluggish in cooler temperatures, which makes getting closer less dangerous. Spraying after dark is very effective since all the wasps will be in for the evening.
Watch and learn
In over 20 years of working in this industry, I have gotten stung twice by Yellow Jackets…on the same hand…in the same tree…I guess the second time qualified as a “dumb as a rock” moment. If you see wasps in your yard, stop and watch what they are doing. Then watch where they go. If they are just hunting, tell them “Thank you” and both of you can go about your business. Since I believe that it’s best NOT to kill wasps randomly and with impunity, I looked for an article to give you great information (because wasps are pretty interesting). I really had to hunt for one that wasn’t just about destroying them. This article is a good mix of information on many types of wasps and how to live with them, including advice on discouraging them, before they become a problem. https://pods.dasnr.okstate.edu/docushare/dsweb/Get/Document-2284/EPP-7305web%20color.pdf
Mantra of the week
“Wasps do not deserve to die, just because I am afraid of them.” Repeat 3 times, when you see a wasp.