To dry hydrangeas:
Doris to help get rid of bugs in produce from the garden my Mom always washed her stuff in salt water, the bugs hated it and died. Maybe that would work for your flowers, just a thought.
Linda
As far as drying hydrangeas goes, probably the best way to dry them is to bunch a few stems together, secure with a rubber band and turn upside down to dry in a dark, dry area, an attic is great. They will lose a little color, but will dry in good shape if not put in too large of bunches. The bugs die or leave.
Kim
I heard something on the radio about this. Take shot glasses and fill them with water. Put one stem in each. If you don't have any shot glasses, take a vase and put a shot glass full of water (about 2 ounces) for each stem. This allows them to dry slowly and not lose their color.
To kill the bugs: cut a flower from the plant. Get a large jar, like mayo jar, and put 1/2" of alcohol in the bottom. Hang the flower in the jar but don't let it touch the alcohol. The fumes from the alcohol will kill the bugs and they will fall out. Should take no more than 1 hr. for each flower.
This is how bug collectors catch bugs too. They get a net shaped into a funnel with a jar at the bottom. The jar contains about 1/2" alcohol. When the bugs hit the net they roll into the jar and die.
Check out these photos.
The blue dried hydrangea beauties share the table with a doll dressed in Victorian attire, her red hair is adorned with a hat that frames her porcelain face and the emerald green colors of her dress and accessories. The hydrangeas were picked in a country setting, dried and placed on a vintage clear plate.