AMES, Iowa – Plant propagation is fun and easy in the home and is a good way to inexpensively increase plant numbers. Horticulturists with Iowa State University Extension and Outreach discuss plant propagation methods best suited for several common houseplants. To have additional yard and garden questions answered contact the Iowa State University Hortline at firstname.lastname@example.org or 515-294-3108.
Christmas cacti are easy to propagate. Remove sections of the plant consisting of two to five flattened stem segments. Cut or pinch off each section at a joint. Allow the pinched ends of the cuttings to callus overnight. The following day, fill a pot or other container with perlite or coarse sand. Water the rooting medium and let it drain for a few minutes. Insert the pinched end of each section about 1 inch deep into the perlite or coarse sand. Firm the perlite or coarse sand around the sections to keep them upright.
After all the cuttings are inserted, water the rooting medium again. Allow the perlite or sand to drain for a few minutes and then set the container in a brightly lit location. Periodically examine the cuttings over the next several weeks and water the rooting medium when it begins to dry out. The cuttings should root in about six to eight weeks. When the roots are 1 inch or longer, plant the cuttings in a pot using a well-drained potting mix.
The common rubber tree (Ficus elastica) can be propagated by air layering. Air layering is a procedure used to induce roots to form on a plant stem while it is still attached to the parent plant. Complete or partial girdling of the plant stem interrupts the downward translocation of carbohydrates and other compounds. The accumulation of these compounds promotes rooting at the point of injury.
Materials that are needed to air layer a rubber tree include a sharp knife, sphagnum moss, a sheet of clear plastic, twist ties and a rooting hormone. The procedure for air layering a rubber tree, weeping fig and other woody Ficus species is as follows.
Select a point on a stem about 12 to 18 inches from a shoot tip. Remove any leaves in the immediate area. Using a sharp knife, make a cut completely around the stem. The cut should penetrate down to the woody center of the stem. One inch below the first cut, make a second cut completely around the stem. Finally, make a third cut connecting the previous two cuts. Remove the ring of bark. Scrape the exposed surface to insure complete removal of soft (cambial) tissue. Dust a small amount of rooting hormone on the exposed surface. (The rooting hormone promotes rapid root development. However, the stem will root without it. It will simply take longer.) Place one or two handfuls of moist sphagnum moss around the exposed area. Wrap a piece of clear plastic around the sphagnum moss. Make sure none of the moss protrudes out the ends of the plastic wrap. Secure the plastic wrap above and below the sphagnum moss with twist ties.
Roots should appear in the sphagnum moss in several weeks. When a good root system has developed, cut off the stem just below the bottom twist tie. Remove the twist ties and plastic sheet and pot the rooted stem in a well-drained potting mix.
African violets are easily propagated by leaf cuttings. Select a firm, healthy leaf and cut it off with a sharp knife. Leave 1 to 1½ inches of the leaf stem (petiole) attached to the leaf blade. Fill a pot with a moistened 50:50 mix of vermiculite and coarse sand. Insert the petiole of each leaf cutting into the rooting medium at a 45-degree angle. Firm the rooting medium around the petiole of each leaf cutting. After all cuttings are inserted, water the rooting medium and allow it to drain for a few minutes. Next, cover the cuttings with a clear plastic bag. Secure the plastic bag to the pot with tape or a rubber band. (The enclosed environment drastically reduces the loss of water from the leaf cuttings and prevents them from wilting and dying before they have a chance to root.) Set the pot in a brightly lit location.
Roots usually form in three to four weeks. The leaves of new plants usually appear in six to eight weeks. Several plants usually form at the base of each petiole. Separate the plants by carefully pulling or cutting them apart. Pot up plants individually into containers using a well-drained potting mix.
PHOTO: Rubber tree