[pottylotty1]

Can anyone shed any light on the above problem? I have also noticed die back on some of the leaves.

[New shoot]

I think you have foxed people there plottylotty.  Could you put a picture on of the roots?

If it one of the small top grafted willows, they are very thirsty and can suffer die back of the leaves if they dry out in a pot.  Usually they recover if the damage is pruned off and they are kept well watered 

[Trikidiki]

Die back of the shoots on willows could be caused by anthracnose, I have one in the field next to my plot that appears to be suffering from it. No idea about the roots.

[8doubles]

I have seen an ash like fungus on the roots of trees and hedges and always thought that it was one of the beneficial fungi that help the plant to grow .

[mumofstig]

I have seen an ash like fungus on the roots of trees and hedges and always thought that it was one of the beneficial fungi that help the plant to grow .

I was going to say the same thing, the die back may just be the awful weather!