The arborvitae pyramidalis (Thuja occidentalis Pyramidalis), also known as the pyramidal arborvitae, is a tall but slender evergreen tree. The pyramidal arborvitae reaches 15 to 25 feet tall and 3 to 5 feet wide at maturity. Due to its compact growth habit and evergreen foliage, the pyramidalis arborvitae is most often grown in groupings to create hedges or privacy screens. This arborvitae grows best in USDA Hardiness zones 3 through 8, where winters are colder and minimum annual temperatures are as cold as minus 35 degrees F.
Plant the arborvitae privacy screen on a site that has full to partial sunlight and well-draining soil.
Insert wooden stakes to represent the pyramidal arborvitae trees along the desired privacy fence line. Space the stakes every 3 feet, and tie a string along the stakes, ensuring that the line is straight.
Dig planting holes at each of the wooden stakes that are twice the width and the same depth of each arborvitae's root ball. Loosen the soil on the walls and bottom of the planting holes with a shovel.
Set the arborvitae pyramidalis tree's root ball into the planting hole, standing the tree up straight. Ensure that the point at which the top of the root ball meets the trunk is 1 inch above the ground surface. Remove the tree and add soil to the bottom of the planting hole if needed to achieve the correct planting depth.
Refill the planting hole about halfway with the displaced soil, and then water the soil to help it settle around the roots. Backfill the planting hole the rest of the way and water it again to saturate the soil down around the root ball.
Spread a 2- to 3-inch-thick layer of bark mulch on the ground around the base of the arborvitae pyramidalis, spreading the mulch so that it covers the entire root area. Keep the mulch about 2 inches from the trunk.
Repeat the planting process for each pyramidal arborvitae until you've planted your entire privacy fence.