The Thuja plicata, also called Giant Arborvitae or Western Red Cedar, is a low maintenance evergreen that can be planted to create a tall hedge. Thuja plicata should be protected in areas where heavy winter snow can cause damage to the branches. The trunk of the Thuja plicata is fibrous and deep red in color, making it appealing for use in basket weaving.
The Thuja plicata is a large growing evergreen arborvitae that reaches a height up to 80 feet and width up to 20 feet. The foliage is a rich green color with white markings on the underneath and has a tansy-like aroma when crushed. Thuja plicata produces 1/2 inch sized cones that can be used to propagate additional trees.
The Thuja plicata arborvitae grows best when planted in a moist loam soil in USDA growing zones 5 through 8. A sandy loam or clay loam soil is preferred as long as there is no standing water. The trees should be planted at least 15 feet apart when used as a hedge to allow room for the branch spread.
Care and Maintenance
The Thuja plicata hedge grows best in soil that is moist. Do not over water or cause standing water around the stem as this can cause root and stem rot. Give the hedge supplemental water during the hot summer months and periods of drought by watering with a soaker hose at ground level. Place organic mulch around the stems and over the root ball area to increase moisture retention in the soil. Provide a balanced fertilizer in the spring to promote woody growth that will strengthen the Thuja plicata tree. Shape the hedge by pruning in early spring before new growth appears.
The Thuja plicata arborvitae tree can be propagated by collecting cones just before they fall from the tree and extracting the seed. Sow the seeds in a small growing container in spring or sow them outside once the soil begins to warm. Propagation can also be done by taking semi-hardwood stem cuttings in mid-summer. The cuttings are planted in a rooting medium and grown in a warm, moist environment until roots are one inch or longer in length.
The Thuja plicata arborvitae tree is susceptible to bag worms and spider mites. Bag worms are caterpillars that kill evergreen branches by consuming the foliage. The worm eggs winter over by living in a 2 inch bag on the female worm. Control the worms by removing and destroying them in the fall or winter season or spraying the hedge with an insecticide when the worms are in the larvae stage. Spider mites are small spiders that feed on the arborvitae foliage and cause the needles to turn brown and fall off the tree. The mites can be removed by spraying the tree with a sharp stream of water and applying an insecticidal soap.