There are some wasps lingering around my roses this year, last year they just buzzed through, however there are also large quantities of aphids this year. I believe the wasps are eating them, so I can't just set out traps.
Wasps freak me out, so how do I garden WITH them?
If you can't find the nest there's not much you can do. Maybe you can watch and try to do some gardening really early before they come out or wait until dusk when they leave. Aphids, unless it is a major infestation, are pretty easy to get rid of with a blast of water or a spray of mild soapy water.