Thuja Green Giant trees are easy to grow, tolerant to drought, and insect- and disease-resistant. In addition, they can grow in almost any type of soil and are wind- and ice-resistant. With little work from the gardener, the species grow in uniformity and create privacy screens. Green Giant trees grow an average of 3 to 5 feet per year once they are established. Pruning them will enable you to control just how much they grow.
Buy sharp pruning shears from a gardening store or nursery. Clean them before each use to ensure you don't spread disease from one plant or tree to another.
Remove dead, diseased or weak branches as soon as you spot them. Find the point where the limb connects to a healthy one and clip it at the V-shaped joint.
Expect the outer few inches of Green Giant trees to turn brown after the winter because the wind dries them out. Trim off all the brown with hedge clippers around the first of April. New growth will be in place by the end of May.
Climb a ladder to reach the top portion of the tree. Use a measuring tape to determine how tall you want it to be, especially if you are trimming more than one tree and want them to be similar in height.
Trim Green Giant trees once a year to the height you desire. Standing on the ladder, use a hedge trimmer to cut a few feet off the top of the tree.
Create a hedge out of the trees by cutting off most of the height. Use the trimmer to create a box-like shape or rounded shape.