Hi Joan and welcome to GoY, could you be a little more specific about the feeding, watering and pruning. We do absolutely nothing to our Kilmarnock Willow except to prune it when it starts wandering across the road.

Accidental weedkiller application? Excessive or recent Lawn Feed and Weed application to the lawn?

many thanks for the advice i think the solution might be the feed and weed i applied to the lawn although i did this in april and the tree has only just died. the label says to prune after the catkins and feed regularly. jayhay

I've never heard of pruning a Kilmarnock Willow on a yearly basis... You might want to scrape away a little of the bark and see if there is green underneath. If there is them you have only lost this years leaves. Lots of water to keep it going.

Unlikely to be the Weed and Feed if the last time you applied it was April - in the last couple of weeks, maybe, but not that far back. Moongrower, in the average sized garden here in London, Kilmarnock Willow would be pruned annually to keep it in check - don't forget we don't have huge areas to garden in like you do up there. Or most of us don't anyway.

It is rare that we prune anything I must confess... though yesterday I raised the canopy on several of our trees.