Propagating Woody Ornamental Plants by Pat Naughton

You don’t need a greenhouse to propagate your favorite perennial. All you need is a small cutting, rooting medium, rooting compound, and a plastic bag. The four main types of stem cuttings are herbaceous, softwood, semi-hardwood, and hardwood. The terms reflect the growth stage of the plant. This is the main factor influencing whether or not cuttings will root. The method of propagation is essentially the same with hardwoods requiring more cuts.

The best time to take cuttings is in the morning when the plant is fully turgid, full of water. It is important to keep the cuttings cool before putting them in soil. Look for shoots with new growth. The terminal end of a shoot is the best place to take cuttings from. Remove four to six inches with a knife or pruning shears. Remove the leaves from the lower one third. Cut the remaining leaves in half to reduce the need for water. Remove any flowers or flower buds which will take energy away from growing roots.

Semi-hardwood and hardwood cuttings require deliberate wounding to stimulate root growth. Hardwoods, like magnolias and evergreen rhododendrons, respond well to heavy wounding where an inch of the bark is removed from the end. Light wounding involves making shallow vertical slits in the lower third of the cutting. Many conifers benefit from this type of wounding. This is not necessary for herbaceous plants like coleus, chrysanthemums, and dahlia.

The rooting medium should be sterile, void of fertilizer, drain well but still able to retain moisture. Rooting medium can be made from coarse sand, pine bark or a one-part peat moss and sand or perlite by volume.

It is important to use a rooting compound to stimulate root growth. Pour some of the rooting compound into another container to dip the cuttings in. That way the entire bottle does not get contaminate. Dip the lower third of the cutting in the rooting compound. Make a hole for the cutting in the medium and place the cutting in it. Give the cutting a little water. Place a plastic bag or a plastic milk carton with the bottom cut out over the plant. This will help to keep the humidity up. Place the container in indirect light. The plant can be left in the container until spring. To improve the chances of survival, transplant the plant into a larger container or in a bed before planting directly in a landscape.

For more information on propagating cuttings, search NC State Extension publications Plant Propagation by Stem Cuttings and North Carolina Extension Gardener Handbook Chapter 13 Propagation.