Salix Iintegra 'Hakuro Nishiki'

 I was given the above standard Salix about 3/4 years ago and planted it in
my front garden. As the soil is chalky and very free draining I dug a large
hole and planted it in a proprietary shrub compost.

Instead of growing into a large plant as the books say and as others round
here have, the flower stems have become smaller and fewer and as of today
the few pathetic remnants that appeared this year appear to have died off.
There is still life in it though because suckers frequently appear on the
stem.  However the bark seems to have peeled off in places.

I understand that this plant needs lots of water which I have tried to give
it but I admit to not watering through the winter, could this be the
problem?  All advice appreciated.

Derrick