What till nite, or very early morning. They will go back to their hive/den. Either spray the shitz with wasp foam their hive, or burn their ground nest up.
I have been attacked before ... take no prisoners ...
I get powdered bondide spider and ground bee killer. The label says it has permethrin in it. Sprinkle it on the entrance at night and they drag it in themselves. Bye bye bee.
Agree on the powder sprinkled at the opening (beware - ground bees generally have 2 openings). I used Sevin powder and just put a good scoop or mound over each opening. They take it into the hive when they land.