Answer: I think one of the best choices for the site you describe is Thuja pyramidalis (American Arborvitae). These tall, narrow evergreens reach 10-15' in height yet remain only 2' in width. I keep mine topped at 8' and they make perfect hedging plants. Plant them 3' apart and they'll grow into one another and look like a lovely green screen.
Q&A Library Searching Tips