I rescued a weeping willow from a disused garden. It had grown out of shape and was a bit of a mess. It is approx. 7 yrs. old. It has thrived now but being new to this I need help to prune it. I have read your piece on it but, unfortunately, I have let loads of shoots grow from the bottom. They are 3 ft long now. Any suggestions on getting it back to shape without harming it?