Need to screen out a neighbour or an unsightly building next door?! At Egardens.com.au this is by far our most common request - for the tallest trees to create a screen. Most of these guys below can reach heights of up to 8m plus. Just remember that plants are living things and height growth is always dependant on the plant's environment and how happy they are in their position with sunlight, water and soil playing a major part in how tall the plants will eventually reach at maturity in any given space. OUR TOP 10 TALLEST SCREENING TREES ARE: 1. CUPRESSOCYPARIS LEYLAND..