Propagating House Plants

Most homeowners are looking for economical ways to replace or increase their selection of house plants. One way is by propagation. Propagation, which is the word for reproducing plants, often scares people, but it should not. Simply, it means obtaining new plants from old ones and there are several ways this is done-all relatively simple. Many different plant parts can be used, including seeds, leaves, stem pieces, bulbs and root pieces. Most house plants can be propagated from at least one of these plant parts.

There are two basic methods of plant propagation - sexual, by seed and vegetative or asexual, by means of some vegetative part such as a shoot, root or leaf.

House plants are seldom propagated from seed. Most house plants, particularly foliage plants, are not grown in an environment conducive to flowering. The inadequate light, high night temperature and low humidity found in most homes doesnot favor the buildup of carbohydrate needed to initiate flowers and produce seed.

The most common and satisfactory method to propagate house plants is from cuttings. A cutting is a portion of a plant taken from a parent plant. There are many types of cuttings, but the most commonly used are those made from stems and leaves.

Leaf cuttings are of two types--those where new plants arise from the leaf blade, such as sansevieria (snake plant), rex begonia, and kalanchoe and those where the roots and shoots arise from the base of the petiole, such as African violet and gloxinia.

Sansevieria leaves may be cut into sections about 2 to 3 inches long and stuck in a moist rooting medium (mixture of 1/2 peat and 1/2 sand) about one inch. It is important that the section remain right side up. Roots and a shoot will form from the section and should be removed from the leaf section when it is 3 to 4 inches high. The variegated sansevieria will not reproduce true to type using this method. To retain its characteristics, it must be propagated by division of the original plant.

Leaves of rex begonia and other fibrous begonias develop young plants from their primary veins. Make small cuts across the larger veins on the undersurface of the leaf. Then lay the leaf right side up on a moist medium. Use hair pins or wire to hold the leaf in contact with the medium. New shoots should appear in about two weeks. When the new shoots are 2 to 3 inches high they can be transplanted.

African violets and gloxinias can be propagated using entire leaf (leaf blade plus petiole) cuttings. Cut the leaf from the plant leaving 1 - 1.5 inches of petiole attached to the leaf. The leaf cutting should be stuck into the rooting medium only deep enough to keep the cutting upright, and at an angle.

Most house plants root well from a stem cutting. Cuttings of 4 to 6 inches in length should be taken from healthy, vigorously growing plants. Make a clean cut about 1/4-1/2 inches below a node (joint) with a sharp knife. Avoid crushing the stem. Remove leaves from 1 - 2 inches above the cut end of the cutting. This makes it easier to stick and reduces water loss from the cutting.

To hasten rooting, you can dip the cut end in a rooting hormone. Stick the cut end of the cutting in a rooting medium about 1 - 1 1/2 inches deep and firm the medium so that the cutting remains upright. Stem cuttings can be rooted in plastic bags or in containers covered with plastic bags. The plastic cover allows the cuttings to breathe but prevents loss of water. The cuttings should not require watering until they are well rooted.

The plastic covered container should be set in a warm well lighted place but not in direct sunlight. Transplant cuttings to individual pots when roots are about 1/2 to 1 inch long. Most cuttings will be rooted from 2 to 18 weeks after sticking.