If you want to go ahead and destroy the hornet’s nests now, a method that I referenced in a different thread worked well for me. I have used that same equipment to flame another one this last year. Since your nests are nearer to the ground I would suggest waiting until after dark to give yourself a little more safety.
I took the quick connect propane fitting that they sell at hardware stores and de-limited it (I can explain the method in a PM). I connected that to a 100 foot long pneumatic hose that has a male QD fitting on the other end. That end I hose clamped to the telescopic pole. Connect the propane tank, crack the valve and light the gas coming out the QD fitting, adjust the flow to create flame separation and get to flaming the nest.