As you can see in the picture below, the willow is now dormant. All the leaves have fallen, and the branches closely resemble the original whips that I bought. I suppose they should, as that's what they were! In the background you can see a yellow stripe which I have sprayed, ready to plant next years rotation. I plan to plant another 2 rows with 100 trees in each, entirely from the whips I trim off this years trees.
Interestingly, the tops of most of the whips, above where the branches have finished, appear to have died. I guess there is no need for life beyond the uppermost branch. the pic below shows this quite clearly.
I have now erected a tall electric fence to keep deer out. As there is no power nearby, I selected a 12v battery fence and installed a solar panel to charge the battery. so far so good! This also means that I can have animals in the rest of the field without risking them eating my willow, which is apparently very appetising to most animals. The fence cost me €50 for posts, €120 for energiser and tape, €25 for isolators and €75 for a battery. Total € 270. I had the solar panel lying around.