I am looking to create privacy with 3 trees next to a deck between two houses. I need something fast growing, vase shaped or narrow and about 15 to 25 feet tall and 10 to 15 feet wide. There is a row of viburnum summer snowflake there now, but they will only get 8 to 10 feet tall, so I thought that I could plant 3 trees within the row of viburnums to create taller privacy and the viburnums could fill in the space below the trees. Does anyone know of a Japanese Maple that could fit those requirements or another tree? I am in zone 6 and the area gets full sun.