The Thuja 'Green Giant' (Thuja standishii x plicata) is a fast-growing, pyramid-shaped tree in the cypress family that makes a striking specimen planting in the large residential landscape. The United States Arboretum calls it an "evergreen sentinel in the landscape." Considered a replacement for the disease-prone Leyland cypress, Thuja Green Giant is easy to care for and is disease-resistant.
Water the Thuja Green Giant only during periods of drought. Water it out to the drip line (the farthest reaches of its branches) until the soil is saturated, and then allow it to dry completely.
Fertilize the Thuja Green Giant with a slow-release 10-10-10 fertilizer at the rate suggested on the package twice a month in spring and once a month in the summer. Withhold fertilizer from October through February. Always water after fertilizing.
Maintain a weed and turf-free area within a 3-foot radius of the tree. These plants will compete with the Thuja for water and nutrients.
Prune the Thuja Green Giant to keep it to the size you desire. That is the only pruning that is required for this easy-care tree.