How to Maintain an Arborvitae Shrub

With their tall, dense growth and evergreen foliage, arborvitae (Thuja occidentalis) make excellent plants for privacy hedges. These columnar shrubs prefer full sun, and loamy well drained soils, but they will tolerate a variety of soil conditions. Although green is the most common foliage color, some arborvitae cultivars have foliage ranging from golden to copper. If planting an arborvitae as a privacy hedge, space plants 2 to 3 feet apart. Once planted, arborvitae are low-maintenance shrubs but do require some care to stay healthy. 

 

Feeding

During the first five years of growth, your arborvitae will benefit  from an annual feeding. In the late spring or early fall provide your arborvitae with a fertilizer that contains twice as much nitrogen as phosphorus. For example, the numbers on the label will read as 16-8-8 or 20-10-5. Compost is also an excellent organic food for your shrubs. Give the plants one-third pound of food for every foot of height. So, a 6-foot tall arborvitae will need 2 pounds of fertilizer or compost. Use a trowel to work the food into the soil around the plant. Avoid letting the food come in direct contact with the trunk or roots. After five years, your arborvitae does not need to be fed unless you want to encourage it to grow fuller or taller. 

 

Watering and Mulch

During the first year of growth, your arborvitae will need enough water to keep soil moist but not wet. After the first year, you only need to water during dry periods. When the weather is dry, provide enough water once a week to thoroughly soak the soil around the plant but not enough to leave standing water. To help retain soil moisture, place a 2-to-3 inch layer or mulch around the shrubs. To reduce rot, avoid letting the mulch come in contact with the trunk of the arborvitae. 

 

Pruning

In early spring, your mature arborvitae will need to be pruned to help its shape, encourage fuller growth and to limit its height. Use hedge clippers to trim along the side and top of the shrubs to cut it to the shape and height you prefer. Use loppers or a pruning saw if any of the top branches are too thick for the hedge clippers to cut through without force. A good height for most privacy hedges is 8 feet. 

 

Winter Care

Although arborvitae are frost-tolerant; heavy winds, snow, and ice can bend and break the branches, possibly leaving bare spots. If harsh weather is predicted, you can help your plant by tying the branches. To do this, tie thick rope or rubber straps around the plant from top to bottom. The entire plant does not need to be covered with rope, just enough to hold the branches - think of the red stripe along a candy cane as you tie the shrubs. Do not use wire or string since these can cut into the foliage and bark of your arborvitae.