The most common method used to propagate plants is by cuttings. A wide range of plants, mostly flowering plants, can be propagated by removing stem sections and placing them in propagation soil. Stem cuttings include herbaceous plants (geranium, coleus, and carnations), soft wood plants (lilac, forsythia, crape myrtle), semi hardwood (lemon, camellia, and holly), and hardwood plants (fig, grape, crape myrtle, rose and willows).
A sharp knife or pruners are used to remove four to six inch
long stem sections. A cut is made just below the node so the new roots can free
develop from it. Basal leaves are removed from the lower half of the stem making
the installation much easier into the soil.
If the stem section is cut above a bud or leaf, then the stem should include one or two node sections of the stem. Stem cuttings are often made by propagators when many cuttings are needed and only a few plants are available. Keep in mind that stem sections may require several additional weeks to develop roots as compared to tip or half-ripe cuttings.
In some plant groups leaf cuttings can produce new shoots and roots. For example, Begonia rex, Bryophyllum, Sansevieria, Tolmiea, and African violets can develop new leaves if the leaves are placed on top of the propagation soil or can be inserted into it. After roots develop and the new plantlets mature, the old leaf usually dies.
African violets, Sanseviera, and Crassula produce new plantlets from meristematic cells located at the base of the leaf blade or petiole. African violets are usually propagated with a portion of the petiole attached to the leaves.
Leaf-bud cuttings are started from only a few plants. This type of cutting consists of a blade, the petiole, and a short piece of stem with an attached bud. Blackberry and hydrangeas are typically prepared as leaf bud cuttings. The cuttings are inserted into the propagation soil so that the bud is one-half to one inch below the surface. High humidity and bottom heat enhance the success of rooting.
Root cuttings are taken from young plants in late winter or early spring when the roots are well supplied with stored food. Polarity of the stem is important, so avoid planting stems upside down, the top of the stem may be made with a straight cut and the bottom end with a slanting cut. The following plants can be propagated by root cuttings: kiwifruit, silk tree, bleeding hearts, California poppy, edible fig, St. Johnswort, liriope, goldenrain tree, phlox, red raspberry, horseradish, and lilac.