We started planting willow as a hedge/windbreak/feed source a couple of years ago. Here in West Wales it is both windy and wet and they seem to be thriving rather than just sirving. A few striggle when our Herdwicks really attack them )especially when they jump the stock fence and binge on the shoots) but we have taken to cutting the stems back and planting the new shoots to replace the damaged ones. Also helps to thicken out the base. Come the summer we chop the tops and feed them to our Angora hoats who go absolutely crazy for them.
We have planted three rows between stock fence and it is generally OK. Last year added a few hazel, silver birch and hornbeam to add variety. The hazel is growing slowly (the herdwick eat it faster than it grows!!!) but the hornbeam seems to be doing OK.
As for variety we opted for hybrid willow sticks (60cm) from Bowhayes Trees which were a reasonable price, although we are now self sufficient in replacement whips to plant.
We could have applied for a grant for the planting but as always seems the case, the terms and conditions made it not worth the effort. A 1m gap between the trees and the fence would lose too much valuable field space, we can tolerate a certain amount of browsing, but mainly they wanted high percentages of blackthorn which was exactly what we were trying to get away from. Spend most of our time getting rid of blackthorn (and barbed wire) and have the scars to prove it - hate the stuff!!!
Willow may not be the most diverse hedgerow (although apparently it supports a lot of critters!) but it grows really fast (6-8ft in the first year and then starts thicken out as you cut back) and we also have about 3 acres of ancient wet woodland (including 300 year old oaks) and another 1.5 acres of mixed deciduous woodland we planted when we first moved in (now pushing 15-30feet high after 8 years) so I can live with my conscience on this one.