Some mature quickly into dense hedges and others develop with you, over time.
When planting your living screen, don't plant in a straight line. Zig-zag the trees to give a fuller effect and to allow the trees to get air and the sun. This will also help the hedge give with the wind, preventing breakage and wind tunnels.
Choose a couple of your favorite evergreen varieties. It's wise to plant more than one variety of evergreen in a border so that disease and pests won't destroy the whole planting.
Here are some top choices: green hedges