Wintertime Propagation of Trees and Shrubs
by Anne Moore
Have you thought about increasing your shrubs and trees by taking cuttings? Cuttings taken in the winter, during a plant's dormancy, are called hardwood cuttings. If you'll be pruning your trees or shrubs for shape and size, you will probably have some cuttings worth trying to root.
Hardwood cuttings are taken during the wintertime while plants are dormant. The ideal time is just after the plant goes dormant in the fall or just before the buds open in the spring.
Hardwood cuttings should be straight and thick, with no branching, and can be up to 9 inches long. Extra length, which stores extra food supplies, is needed in the wintertime since rooting takes longer. An added benefit is a larger plant when it has rooted.
When you are taking the cuttings, make sure you know which way is up. A cutting will only root on the "bottom end". You can mark the top with a felt tip pen if it's difficult to tell top from bottom. Remove any soft tips and leftover leaves. Evergreens should have the needles or leaves removed from the bottom half of the cutting.
Fill pots with prepared soil-less potting mix made up of a mixture of peat, perlite and bark. Do not use garden soil. The mixture should be sterile and fast draining. Do not let the mix dry out but also don't keep it soggy wet.
The container should be large enough to hold three or four cuttings. Take more than one cutting as insurance because not all will root. Make a fresh cut by trimming the cuttings to a node (a bump on the stem where a sprout would occur), then dip the bottom of the cuttings into rooting hormone and finally stick them in the prepared pots.
The cuttings should be buried one half of their length, tops up. Slip the pot into a plastic bag or make a little greenhouse cover by cutting off the top of a plastic soda bottle. Keeping the cuttings under plastic will conserve humidity.
Put evergreen cuttings in a brightly lit area indoors. No direct sun, the cuttings will cook under plastic. Deciduous cuttings, the ones with no leaves in winter, do not need light until growth is seen. Supplying bottom heat under both kinds of cuttings will speed up the rooting process. Check daily for moisture.
It does take patience. Some woody plants can take up to five months before they are ready to be potted up. If you feel resistance with a GENTLE tug on the cutting, it is starting to root.
After danger of frost has passed, take the pots of rooted cuttings outdoors to the shade. Be sure to remove the plastic covers. Gradually move the cuttings to sun, a little more exposure every day. This is called "hardening off". Skip this step if they are shade plants. Do not let them dry out. Feed them with a little weak houseplant fertilizer. In the fall, pot them up singly in larger pots or move them to their new homes in the garden.
Some easy plants to try are willows, forsythia, Hinoki falsecypress, Leyland cypress, sweetspire, hemlocks and yews. Most hollies can be difficult but 'Nellie Stevens' holly is easy. There will be failures. Be warned, though. After a success, you will not be able to prune anything without trying to root the leftovers.
Copyright 2003, Anne Moore
Rooting Hormone can be found at nurseries and garden centers. Ken Druse, has a beautiful book illustrating and teaching the methods of propagation, titled "Making More Plants".
Anne Moore is a member of the Garden Writer's Association and a writer in the Southeast United States.