Root stem cuttings of white cedar for faster results than growing from seed. White cedar (Thuja occidentalis), known as arborvitae, is one of the most popular evergreen shrubs available for hedging and privacy screens. Thick, green foliage forms a dense, pyramidal shape that reaches heights of 25 feet with a spread of 5 feet. White cedar grows slowly and so will your rooted cuttings, but if you follow a few simple instructions, you'll soon have healthy offspring from the mother tree.
Take cuttings from white cedar trees in late fall, winter or early spring, when trees are fully dormant and sap is running very slowly. This will cause less injury to the tree and to the cutting itself. Plan for early morning for the slowest sap movement of all. Fill medium-size flowerpots with a soilless potting mixture in preparation for receiving the cuttings.
Cut three to four 6-inch stems from this year's growth of cedar branches with a sharp knife. Test branches with your fingers. They should be flexible and light brown, with plenty of foliage. Last year's wood will be darker and stiff. Cut at a 45-degree angle to leave a large surface for absorbing rooting hormone and moisture. Do not cut straight across the stem.
Pinch off foliage from the bottom half of each cutting. Wrap the cuttings in wet paper towels and place them in a bowl of ice to keep them cold and moist until you can root them. Don't let them stay there for more than an hour or two.
Dip the bottom 1/3 of the white cedar cuttings in rooting hormone, covering the surface completely. Tap off excess hormone and poke the cuttings in the soilless potting mix, covering the bottom half of the stem. Pat the mixture down firmly around the cutting with your fingers so the potting mix makes firm contact with the stem.
Put the flowerpots in clear plastic bags and seal their tops with twist ties. Place them in a warm room with bright, indirect light. Open and mist the cuttings each day with a spray bottle of water. Reseal the bags to trap humidity inside. Test the cuttings after four weeks. If they resist a light tug, rooting has occurred.
Transplant the white cedar cuttings into pots of regular potting soil after three months. Take them outdoors so they can acclimate gradually. Transplant your new white cedar trees into the landscape in late fall.