Sorry your question didn't get answered Sue. Are you wanting to grow it as a tree or shrub? I don't have a dappled willow so I'd better not give any advice but I did find a pretty good website with pruning information. Hope it helps. My only willow is a dwarf arctic blue willow will which is starting to get a little bigger than I expected it to. I may be doing some pruning also.

Also noticed you are new to Gardenweb. Welcome! The Ozarks forum is not as active as it used to be. You know how sometimes there's an awkward silence. We just need some people to get some conversations going so feel free to join in or ask questions. We'll do our best.

Here is a link that might be useful: Pruning Willows for Ornamental Effect