I put in willow slips in spring 2011, out of 100, 85 took, and then when I cut the first years growth back to start them making lots of shoots, I put some more in to fill the gaps, most of which have taken. The largest are now about 12 feet high, and getting quite thick. I think it will be at least 3 more years before I can think if cutting them. Hope this helps! They were really easy to grow- the arrived as 1 foot long slips that we just pushed in to the ground, with plastic guards round to keep the rabbits and deer off whilst they got established