I have planted about 40 8-11 feet cedar trees in my backyard recently in order to block the very messy view of my neighbourâ€™s backyard and gain some privacy. The space between each of them is 2.5 feet. The trees are 30-40 feet away from my house and about 2 feet away from my neighbourâ€™s fence. I plan to trim these trees to a beautiful green hedge after they grow up to the same height at 11 or 12 feet. Now my neighbour starts his concern that the roots of these trees will expand very far underneath and go over to their backyard, where he plant vegetables. He said the roots will destroy our drain system and spread all over our houses. He also threatened me that he will cut the roots if they expand to their backyard. My questions are: 1. Is it legal to plant these red cedar trees in my backyard as a hedge? 2. How tall is the legal height for the cedar hedge? Is there any regulation on that? 3. How far will the root expand at most after a few years? Will they cause a problem to our houses? 4. If my neighbour cut the roots in their side, will these trees die? 5. What should I do to respond him? Can I just ignore him? Thank you for your help.