There are small masses of a foam-like material in my red-twigged dogwoods. What are they?
The foam-like masses in the dogwoods were probably created by the dogwood spittlebug. The dogwood spittlebug is one of several species of this commonly recognized group of sap-feeding insects. Spittlebugs are familiar because of the frothy, wet mass of "spittle" that surrounds the nymphs as they feed on sap from their host plants. The spittle is produced by the immature stage of the insect (the nymph) and is a protection from natural enemies and desiccation.
Spittlebugs cause little harm to plants, so control is usually not necessary. If their presence is unacceptable, wash them off the shrubs with a forceful stream of water from the garden hose.