Question
we have a few Manhattan euonymus shrubs in our backyard that
attract hundreds of hornets with their new growth in the middle of
the summer - is there any way to control the hornets without
harming the bushes?

Answer
Leslie,
The hornets are collecting the pollen from the euonymus flowers. The best way to get rid of the hornets would be to spray the shrubs with a repellent such as Cirtonella or Eco-exempt EC. These natural products will kill on contact as well as repel any further activity for up to 3 weeks.
I would check the area for a ground hornets nest in the area of these shrubs and have them destroyed ASAP.
Good luck.
Ed Gulliksen