American arborvitae

American arborvitae should be watered deeply once a week in the summer months and every other week in the cooler months. When watering, the soil should be dampened to a 6-8 inch depth. If the soil is disturbed during complete saturation, water again to replace the displaced dirt. It is best to water in the morning or early evening so the foliage can dry before nightfall, which helps prevent disease. Be sure to avoid over-watering as this will cause root rot which can kill the plant.

American arborvitae (Thuja occidentalis 'Sunkist') prefers full sun exposure for more vigorous growth, but can tolerate light to moderate shade. It needs at least 4 hours of direct sunlight per day to maintain its bright yellow coloring. The best time of day for providing sunlight for the arborvitae is mid to late morning or early afternoon, allowing it to get the most intense sunlight during the day without subjecting it to burning hot midday sun. During these times, the arborvitae should receive full sun exposure while avoiding exposure to the hot midday sun.

American arborvitae should be pruned in early summer, when the new growth has matured. Regular pruning will help ensure full, dense foliage. For American arborvitae, prune off dead branches first, followed by selectively removing crossed branches, vertical stems, and damaged or weak branches. Prune just after new growth has appeared and mature foliage developed for the season. Avoid pruning in the late summer or fall months, as winter cold can damage tender shoots.