By Peter Gilmer, NC State Extension Master GardenerSM volunteer of Durham County
(Image credit: University of New Hampshire Extension)
The “dead of winter” is an expression understandable when we had two weeks of cold and a touch of snow, not so understandable with temperatures in the 70s. For plants, the winter is a time of dormancy, both for deciduous as well as evergreen shrubs and trees. This time of year for gardeners often means planning, ordering seeds, and waiting for the soil to warm. It is also the right season for hardwood cuttings, a simple but often forgotten plant propagation technique.
Hardwood cuttings (also known as scions) are taken during the dormant stage of a woody plant, including both trees and shrubs, usually involving last year’s growth, and can be considered from the first hard freeze (late November for us?) through bud break in early spring. The technique is simple, fun, and often considered for a favorite plant or when seed propagation for a specific plant is difficult or slow.
(Left) A healthy donor plant, red twig dogwood (Cornus sericea), showing last year’s growth as the reddest of the stems, each about the diameter of a pencil. (Right) Five cuttings, ready to be dipped in planting hormone powder. Each is cut horizontally just below a bud, and at an angle just above an upper bud. (Image credit: Peter Gilmer)
Where, When, and How to Take Cuttings
To be successful, the donor plant must be healthy. The cut is made just below a bud, often near the base of the plant and should be done with the health and final appearance of the donor plant in mind. The stem should be about the diameter of a pencil, and length does not matter initially as the stems taken will be cut again before sticking. The term sticking is used to describe the simple act of pushing the cut stem into the growing media. Plants with suckers and shoots are often good candidates, and juvenile stems do better than more mature ones.
Cuttings are best taken in the early morning on a cloudy day, to minimize sun exposure, and should be placed in an opaque plastic or paper bag, with a moist cloth or paper towel around the base. A cooler (without ice) may be helpful if many cuttings are being taken. Remember, cutting a stem is an injury to the donor plant, and should be done with a sharp tool cleaned with alcohol or a bleach solution to avoid disease transmission.
Once the long stem is taken from the donor plant, that stem is cut again with attention paid to the final stem length, bud locations, and polarity. In general, final cuttings should contain at least one bud that will be below ground, and at least one above ground. The bottom cut is generally made transversely just below a bud, and the upper cut made at an angle just above a bud. Polarity is easier to maintain if the angled cut is always up, and this also keeps moisture from potentially sitting in droplet form on the top of the stem. Stems will not root if planted inverted. The cuttings at this point are generally six to ten inches long, although this depends on the arrangement of the buds. Note that no terminal buds are kept in this technique, as the stems are usually too small in diameter near the top of the stem.
Rooting and Care of Hardwood Cuttings
Some cuttings can be stuck directly into the planting media, but most authors recommend dipping the base of the cut stem into rooting hormone prior to sticking. Rooting hormone can be purchased at most big box stores, usually in a powder form, and should be handled with gloves and eye protection, as the hormone can be caustic to eyes and to skin. Never dip the cutting into the original container to avoid contamination, and don’t use too much. More is not better, and in fact can inhibit root development. The planting media required is not unique or specific. Any commercially available planting soil or seed starting mix will work. It may be important to not have fertilizer already in the media, as new roots form more easily without initial fertilizer exposure. Most media options contain two or more of the following: perlite, pumice, peat, sand, and fine bark chips.
Taking care of the cuttings is relatively easy. The media should be kept moist, but not soggy. It is essential to avoid desiccation of the new cuttings, but cuttings are more commonly injured by being too wet (for example, in soil that does not drain well). The cuttings will need protection from direct sun, temperature extremes, and animal predation. For some this may be as easy as a container on the north side of the house, perhaps with chicken-wire on the top, with the option to move the container indoors during very cold nights.
Roots can take several months to form, so patience is required. The best way to assess root development is to tip over the container, gently dumping the contents. A cutting with generous fibrous root formation will maintain the entire planting media, while minimal or no root formation will allow the media to fall away. The cuttings can be fertilized once root formation is confirmed, and hardened off by gradually increasing sun exposure as leaves begin to form.
Have fun with this technique. It is fine to experiment. If you wonder “Can I take a cutting of this plant?”, give it a try. It is quite useful to research the potential donor plant using basic cell phone techniques. Simply ask Google “What is the best way to propagate “X” plant?”. We recommend searching for research-based information on sites with the domain .edu– such as https://plants.ces.ncsu.edu. For example, the best propagation technique for red twig dogwood is a hardwood cutting, while the best technique for white oak is an acorn. Enjoy this propagation technique in the dead of winter.
Resources and Additional Information
Hartmann and Kester’s Plant Propagation: Principles and Practices, 9th Edition. Pearson, 2018.
NC State Extension Gardener Handbook online chapter on propagation, 2018. https://content.ces.ncsu.edu/extension-gardener-handbook/13-propagation
Clemson Cooperative Extension Home & Garden Information Center online fact sheet.
Article Short Link: https://wp.me/p2nIr1-5B7