Coast Redwoods, Sequoia sempervirens, can be planted close to each other, 3 - 7 feet apart and then pruned and groomed to be a hedge. Ours was planted out of 24 inch containers and within 3 years, a fully private hedge was created. For this one, trees were placed about 4 feet apart and are now 12 feet tall. It is pruned so that the top is narrower than the base so the sun keeps the interior green, not browned which would happen if no light penetrates. Plan your height so that your ladder works! Redwoods are shallow rooted and need to be watered if they are not in a fog zone. Here at the Main Street Tree farm we have a single tree that has a 6-foot diameter trunk and makes quite an impact when you walk up to it through bush and suddenly see the massive giant's base up close.