I would give them a soapy bath.................... after the sun goes down mix 1 teasp liquid hand soap with 1 qt water and spray spray spray..................it might be a tiny bug................in the fall lime them and use horse manure and spray them with dormant oil that will smother any eggs that were deposited....read the label and see if your plant is on the list.......mix the batch according and spray it on.....wear old clothes, hat, gloves, mask and keep children & pets away until it is dry. do this when the sun goes down......that way by morning it should be dry.