Question
Los Angeles - How far from my home should I plant a Fruitless Mulberry tree.  Is 15 feet far enough.?

Answer
Fruitless mulberries have a crown spread at maturity of about 30 feet so 15 feet from your house would be fine. It will be many years before the tree reaches maturity and if it is getting to large for the space you can prune it back then. The problem IF ANY will be from the limbs reaching the house--the roots will not be  problem. Go for it! Make sure the hole that the tree will be planted in is twice the size of the root ball and as deep, mulch around the tree with not more than 3 inches of organic mulch and water good.