Q.tri colored willow tree
My willow is oozing a white, foamy substance from its bark….What kind of care should I be taking?
This sounds like bacterial wetwood, aka slime flux or alcohol flux. Willows are prone to this disease. Bacteria produce gas which makes the sap foamy and often foul-smelling. Check with your state extension service for recommended treatment in your area. Here is what New Mexico extension has to say on the topic. http://aces.nmsu.edu/ces/yard/2000/081200.html