You have several options...
1. call a pest control company and let them handle it.
2. go to Home Depot or Lowes and purchase a can of Wasp/Hornet spray - wait until sundown/dusk - then they are USUALLY in their nest and spray away...
3. If you don't want to use chemicals, use a coffee can hold it under the nest and "shave" the nest down into the can, you can suffocate them or freeze them....all depends upon what you want to do.
I would need to do some research - it might be a myth or I might be confusing it with Carpenter bees - they don't like "fresh paint"...but if you don't want to deal with them - then i would call a pest control company and have them take care of it.
I DO know that if you attack a hornet near its nest - it CAN AND WILL send out a pheromone defense "signal" that will cause the whole nest to attack...that sucks BIG TIME!!!