Yellow jackets in Hugelkultur

So, I’ve got a small hugel style bed about 8’x5’ and maybe 3’ tall. I’ve got the 3 sisters on one half and sweet potatoes on the other. The sweet potato side has clear plastic on it around the plants to help retain heat (we’re in upper Michigan and our growing season is short). Theres yellow jackets nesting in the sweet potato side, I’m guessing because it’s relatively sheltered and dry under the plastic. I’ve tried dumping hot soapy water with essential oils on their entrance, then covering the entrance with a glass bowl. This killed a few but they just relocated their entrance and are still under there. Any ideas that dont require me to use nasty chemicals in my sweet potato bed? Could I maybe drown them out with a hose up above? You can see in the picture that the empty/dead spot is above their nest.

We used to have them in old  gopher holes , Try peppermint based foaming spray AT NIGHT well after all wasps are in nest in ground . Bury any possible entrance with dirt or sand after spraying- good luck!

Could you leave them till hard frost, then harvest the sweet potato after they are dead?  Or do you need to access the area for weeding etc... before then?

Wasps are incredible hunters for grubs and caterpillars. It they aren't being too aggressive, as Artie suggested, could you just leave them be? I had some ground nesters in a raised mint bed last year and they caused me no harm. I've had some in external nests which were in a problem location and sent Hubby after dark with a paper bag which he just surrounded the nest with and then stomped on it.
(I'm very reactive to wasp stings, but not deadly reactive - so we will deal with a problem nest, but try to live and let live if the nest is safe and the wasps aren't out looking for trouble.)

One guy reported putting a plug-in bug zapper near the nest, such that each wasp that got vaporized encouraged more to come out and fight with the glowing thing. Supposedly this vaporized the entire colony, one wasp at a time. I've never tried it, though -- has anyone actually tried this, or known someone who did?

Artie Scott wrote:Could you leave them till hard frost, then harvest the sweet potato after they are dead?  Or do you need to access the area for weeding etc... before then?

I can weed it without disturbing them too much. This is our first year growing sweet potatoes and I’m not sure if they will need to be harvested before frost or not. They should be protected and warmer in the mounds even if the tops get killed by frost. But the wasps will also probably be protected and warmer in there as well.

Jay Angler wrote:Wasps are incredible hunters for grubs and caterpillars. It they aren't being too aggressive, as Artie suggested, could you just leave them be? I had some ground nesters in a raised mint bed last year and they caused me no harm. I've had some in external nests which were in a problem location and sent Hubby after dark with a paper bag which he just surrounded the nest with and then stomped on it.
(I'm very reactive to wasp stings, but not deadly reactive - so we will deal with a problem nest, but try to live and let live if the nest is safe and the wasps aren't out looking for trouble.)

These aren’t necessary causing any problems, besides apparently killing a couple sweet potato plants. I just don’t know if I will be able to harvest the sweet potatoes without getting into their nest. Even if it’s cooler weather when harvesting, I’ll need to dig into the mound and the inside of the mound will probably be warmer than the cool air outside. Plus, my wife fell on a yellow jacket nest as a kid and had to be rushed to the ER. She’s less than thrilled that they are living in our garden!

Artie Scott wrote:Could you leave them till hard frost, then harvest the sweet potato after they are dead?  Or do you need to access the area for weeding etc... before then?

This is our first year with sweet potatoes, but my understanding is that they get harvested around the first frost. I’ll have to dig into the mound though and it will inevitably be warmer in there than it is outside. They could be quite active in there even if it’s cool outside. I can carefully weed around them in the mean time though.

gretchen barton wrote:We used to have them in old  gopher holes , Try peppermint based foaming spray AT NIGHT well after all wasps are in nest in ground . Bury any possible entrance with dirt or sand after spraying- good luck!

I’ve tried hot soapy water with peppermint, lemon and eucalyptus oils. It definitely had an effect but they just made a different entrance. I think I’ll need to drive them out from inside and make the mound less desirable for them. I’m imagining a fat, happy queen in there with a nice dry house and a ton of workers. Maybe flooding it from above with cold water will be enough to drive them out?

Totally get it, Brody, am allergic to bees myself, and yellow jackets in particular!  I was thinking (a) if possible to coexist, you don’t get stung trying to get rid of the nest and (b) pretty sure you can leave sweet potato in the ground through a couple of hard frosts so that you will be sure the nest is no longer active before digging into the hugel.  And of course, (c) live and let live Whenever possible, but if it comes down to your wife or the wasps, then they just gotta go!

I would be extremely cautious about leaving a yellow jacket ground nest intact. I knew a woman who lost her husband to anaphylactic shock from disturbing a ground nest and got multiple stings. But then again, taking it on has its hazards.

We found a ground nest on our old property that had been an old vole hill so there were a lot of entrances and exits. When we killed the bugs and excavated we were astonished at the size and complexity of the structure. The nest itself was about the size of a cantaloupe (at least) and the nest was buried deep and located above easy flooding (they build water traps to prevent flooding). Search for images of yellow jacket nests and there is a lot of good information.

If you leave it, there will be more nests next year from the queens the current nest hatches out.

Persistence will be needed to kill/flood/beat over the head with a club/electrocute the bugs. Be careful.

Just to get more specific, are they paper wasps who have put a paper nest under the plastic?  Or are they hornets that have a hole in the ground just beyond the plastic?  Or are they hornets that have their opening in your mound?  And how far under the plastic is the new opening?

Animals that yank open hornet nests do it at night, in the dark, with little peril to themselves, and so can you.  

If the new opening is not too far under the plastic, can you hold up the plastic with a 2x4 while drowning them with a full force hose of water?  Either completely soak a paper nest, or fill the ground nest with water, really saturate it.  They might have a second, backdoor opening, drowning them from there as well.  Wait an hour or so, go back with a shovel or a hoe and dig the opening larger while holding the hose on it.   Leave it as wide open as possible.  Pin the plastic up for a few days.  You could even shovel more dirt on that end, make it too deep for them to dig their way out.

It's surprising just how winding the opening trail is to the actual nest, so it may be in there a ways.

A few of them will hang around for a couple days trying to put things back together, but they won't be able to, and will give up.   Then find the nest and expose any eggs that are in it.

And if you're not allergic, they say bee stings are good for arthritis  :-)

Cristo, have you ever done that successfully? If so you got lucky or maybe you had different bugs than we did.

We tried with the big nest on our property. Hose on full, at night, heavy clothing and my husband still got stung multiple times. Maybe ours had night vision goggles on, or they just got lucky, but he still got stung. We were at it for multiple nights with the water, closing up entrances/exits and although we probably did some damage, the queen was not harmed. An area five feet in diameter was soaked with water but the bugs created new openings and kept at it. Like I said earlier, we were shocked at the size of the excavated hole and the nest that was in it.

We finally had to use pyrethrin dust to kill them. Not a great option, I know, but since I'm somewhat allergic to stings, we chose to remove the menace to us and our animals. If it was in my garden bed, I would have tried other insecticidal options like dusting all the entrances with DE then using a duster to puff it into the entrances (at night of course). I have no idea if that would work though. Yellow jackets are just damn tough.

A problem with underground nests is that you don't know exactly what you're up against  (i.e., the size of the opposing army and the layout of their fortress) until the war is over. A nighttime assault gives you a temporary element of surprise, but within 10-20 seconds they're awake and boiling out -- half of them from that exit you didn't know about -- with a score to settle.

Cristo Balete wrote:Just to get more specific, are they paper wasps who have put a paper nest under the plastic?  Or are they hornets that have a hole in the ground just beyond the plastic?  Or are they hornets that have their opening in your mound?  And how far under the plastic is the new opening?

Animals that yank open hornet nests do it at night, in the dark, with little peril to themselves, and so can you.  

If the new opening is not too far under the plastic, can you hold up the plastic with a 2x4 while drowning them with a full force hose of water?  Either completely soak a paper nest, or fill the ground nest with water, really saturate it.  They might have a second, backdoor opening, drowning them from there as well.  Wait an hour or so, go back with a shovel or a hoe and dig the opening larger while holding the hose on it.   Leave it as wide open as possible.  Pin the plastic up for a few days.  You could even shovel more dirt on that end, make it too deep for them to dig their way out.

It's surprising just how winding the opening trail is to the actual nest, so it may be in there a ways.

A few of them will hang around for a couple days trying to put things back together, but they won't be able to, and will give up.   Then find the nest and expose any eggs that are in it.

And if you're not allergic, they say bee stings are good for arthritis  :-)

Cristo, they are yellow jackets/hornets. The mound is made of rotting logs, branches and compost covered with several inches of dirt, then mulched with a few inches of wood chips. Then plastic over the top to retain heat. All I know is that they keep entering and exiting the woodchips in one specific spot and just beyond that spot is our only 2 sweet potato plants that are struggling to stay alive. I’m assuming thats where their nest is. I sprayed their entrance with an organic insecticide, covered with a big tupperware and put the hose above the assumed nest spot and let it run for an hour or so last night. Then another half hour or so this morning. Ill scope it out a bit after work today and see if there’s any action. I could remove the plastic, drench the entire bed with cold water and make a slurry of various pungent herbs and oils to spray around any spots they’re coming out of. Other than that, my only other idea is the electric zapper like someone above mentioned.