Hello: I have a number of fairly yound Norway spruce trees on my property and every year, as is the case this year, they grow 2 - 3 foot+ leaders from the top. They look sort of ridiculous and I want to make sure that I don't have sparse growth between the branches as they mature. How much of the top leader should I trim back and what is the best time of year? My friend told me now is the best time, but I'm not sure? It's just the fast growing Norways that are giving me problems and the Colorado's never need pruning.