Yep you can't see the oxidation (wisteria sap) until it has been washed and has come out of washing machine
We are in drought, and my 15 year old wisteria has produced masses of seed pods, and is weeping fine drops of sticky sap.I have removed the seed pods hoping that will reduce the summer heat stress.....have also given it loads of water.
what about sap from a white wisteria that turns red on new concrete?
Yes, I have the same problem. The sap stains the concrete. Anyone have luck removing it?