I wouldn't be putting any chemicals on flowering plants. Instead I've used a hose-type vacumn cleaner and sucked them little buggers along with their webs right off of the plants without harming the ladies and leaving no residue. It's easy with a little practice and about the only thing you have to watch out for is sucking a branch into the hose but a couple fingers used as a screen over the nozzle remedies that. Once done vacumning the plants clean be sure to spray some Black Flag, Raid or other insecticide into the vacumn to kill the mites before they escape and spread.

Good luck and be careful of what you put on your flowers...remember, they will end up in your body soon!