If you have one or more of these trees growing in your yard, the best time to fertilize them is in early spring. American arborvitae trees can be grown in USDA hardiness zones 3 through 7 ...

Fertilizing: You do not need to fertilize arborvitae plants. These conifer trees are tough and self-sufficient, typically accessing the nutrients they need from the soil. Pruning: 'Arborvitae ...