This fortnightly feature was published on July 26, 1996

Helping plants multiply

By Satish Narula

BUYING and keeping plants is one thing and making plants yourself and then seeing them grow keeps the interest alive right from the seed or cutting, to flowering and fruit-bearing.

The biggest advantage of propagation from a plant part (vegetative propagation) is that it is true-to-type. Of the many methods of propagation the method of cutting probably is the most easy and widely used one. This can be successful if we follow the correct method. The cuttings fail because of drying, improper insertion and rotting. Insufficient moisture is the basic cause of the drying, of the cuttings which have to be kept moist throughout. However, do not let water stand in the container where cuttings have been planted, and ensure drainage.

Do not be tempted to take very large cuttings. A large cutting already looks like a grown-up plant but when planted as a cutting, this piece of stem sans roots fails to absorb sufficient water to match water loss from leaves. Hence, the drying.

Give a slant cut at the base of the cutting. This will provide a more cut-end or surface area for water uptake and rooting. Remove all basal leaves, especially from the part of the stem that would be inserted in the sand. This will otherwise rot. The use of a sharp knife or other tools is a prerequisite to propagation. Blunt cuts, tearing or brusing leads to rotting due to invasion of pathogens.

In case of geranium, chrysanthemum, dahlia and coleus the cutting could be four to six inches long. In case of hardy plants like bougainvillea, roses and most of the shrubs, six to eight inches long is taken. Two-thirds of the cuttings inserted in the sand give a better rate of success.

After a few days of inserting a cutting in the sand (or any other suitable media), a few leaves appear. Their appearance is due to the food reserve of the cuttings and not as a result of striking of roots. Do not be curious to pull out the cutting to see whether it has started growing or not.

Leaf cuttings too are used in certain cases. Rex begonia, sensevieria (mother-in-law’s tongue), pepromia etc. easily multiply through leaf cuttings. In peromia it is the leaf petiole (the portion that attaches the leaf with stem) which is inserted in the sand. In begonia a mature leaf is taken and the veins cut at the back with a sharp knife. It is then kept flat (with top side up) on the sand and kept moist and in shade till it gives new plantlets. The leaf of sensevieria can be cut to a length of about two inches and pushed in sand half its length.

The spider plants, saxifraga and kalanchoe are some of the examples of plants that multiply on their own. In spider plants you find new plants with roots on long stems. Similarly in kalanchoe the plantlets appear either at the tip of the leaf or all along its margin.

Air layering is another easy and sure method of plant propagation. A plant portion is induced to root while it is still attached to the mother plant. The method is adopted in rubber plant, schefflera, crotons, some hard-to-root bougainvillea chinese orange, litchi, and Ixoras.

A healthy stem is selected and a ring of bark about one-and-a-half cm. is removed all around the stem by making two circular, skin-deep cuts on the stem. These cuts are then joined by making a horizontal cut at the top with the tip of the knife. The skin part of the stem between circular cuts is then peeled off exposing the wood below. The exposed surface is scratched with the edge of the knife to remove any thread left back.

The exposed portion is then wrapped in wet moss grass in a polythene sheet which is secured at both ends with a sutli. After about a month or so, fresh emerging roots are visible through the polythene sheet. The stem is then detatched from the parent plant and the independent plant is planted and kept in shade for some time.