Don't know where you live in the UK Ron, but if its in the south, wet it hasn't been - cool, yes, but not enough rain to whet a fairy's whistle. On the other hand, after 11 years those trees should be perfectly able to withstand dry periods, unless your soil is very light - have you inspected the trees, bark, stem and leaf, for signs of disease or pest?

Thanks for your input, Bamboo. We live in East Sussex and it has been quite dry here (near to Hastings) but we had some rain in the Spring months (maybe 7-8 mm in all) and this was certainly more than in 2009. The soil is heavy clay, so not light. The trees have been able to obtain plenty of water in the past, as we have seen by the very slow growth of a nearby Rowen. I've checked and there doesn't seem to be any sign of disease - perhaps the answer is to cut it back hard this winter and wait to see what happens next year? Or alternatively to leave the garden hose on at the roots of each tree for half and hour each day? Regards Ron

I was wondering whether it was watermark disease, which does cause die back like this, but Salix alba and its cultivars are usually martyrs to this, rather than S. babylonica. Note that the trees you have only reach full maturity at 15 years, so they're not old yet and won't be for a long time. Check via google for watermark disease symptoms if you want ,but otherwise, I would suggest cutting back to see what happens. If it is watermark, probably best not plant willows there again - try Corylus contorta instead!

Many thanks Bamboo, I think I will cut them back at the end of autumn and wait to see what happens next year.