Our 3 yr old cork screw willow is dying. This spring it put out new leaves all over, in the last 2 weeks they have all turned brown. Why? In early spring, February, we planted Dogwood sapplings near this tree; we punched a small hole, planted and firmed-nothing more than that. Could we have disturbed the roots? Enough to kill it? Cheers.
The planting had nothing to do with this.
There is no remedy for willow canker, except possibly to feed the tree with potash at 30g per square metre each spring for 3 years.