White Oaks Are Dropping Sap

Q: Our newly-purchased 110-year-old home is surrounded by white oaks. We’ve noticed the oaks are dropping sap on our cars. Is this raining of sap normal? 

A: I very much doubt that actual tree sap is coming down from your oak. The more likely source is a small infestation of scale insects or possibly aphids. Both of these creatures suck sap from leaves and twigs and excrete what they cannot immediately digest. This honeydew falls from the tree as small droplets. So, in a sense, tree sap IS accumulating on your vehicles…but it passed through an insect’s gut before dropping. There is usually no need to control these insects. Natural predators will do an adequate job for you.