Propagation is the process of creating new plants. There are two types of propagation: sexual and asexual. Sexual reproduction is the new life that forms from the union of the pollen and egg, drawing from the genes of two parents. Sexual propagation involves the floral parts of a plant. Asexual propagation involves taking a part of one parent plant and causing it to regenerate itself into a new plant. The resulting new plant is genetically identical to its parent. Asexual propagation involves the vegetative parts of a plant: stems, roots, or leaves.
Asexual propagation is the reproduction of the parent plant, so it’s important to start with healthy stock. The five major methods of asexual propagation are cuttings, layering, division, budding and grafting. Cuttings are when we are rooting a severed piece of the parent plant; layering involves rooting a part of the parent and then severing it; and budding and grafting is joining two plant parts from different varieties.
We will be discussing Asexual propagation by cuttings for interior tropical plant lovers here.
Overview in Brief
Starting with a healthy parent plant, cut off leaves below the node, dip in rooting compound and place in a pre-moistened rooting media like water, soil, sand, mixed peat and soil or sand and/or a commercial product such as Perlite.
Many types of plants are propagated by cuttings including both woody and herbaceous. A cutting is a vegetative plant part which is separated from the parent plant for the purpose of regenerating itself, thereby growing a whole new plant.
Tools and materials:
A sharp knife, scissors or pruning shears.
The healthy parent plant
Containers with drainage
Steps: To protect the parent plant from injury, use a sharp bladed cutting tool that has been cleaned in rubbing alcohol or diluted bleach, (one part bleach to nine parts water) to prevent transmitting diseases from any infected plant parts to healthy ones.
Remove all flowers and flower buds from cuttings to allow it to use its energy and stored carbohydrates for root and shoot formation instead of fruit and seed growth.
Note: Rooting Hormones tend to speed up rooting, increase the quantity of roots. We recommend one that includes a fungicide. We like to separate out the estimated amount we will be using in one sitting for dipping cuttings to prevent possible contamination of the main supply. Dip the end of the leaf stem, Petiole and node into the rooting compound.
Put cuttings into a rooting medium such as coarse sand, vermiculite, soil, water, or a mixture of peat and perlite.
The goal of a rooting compound is to get optimum rooting in the shortest time. Best case scenario is that your rooting medium should be sterile, drain well enough to provide oxygen, but retain enough moisture to prevent drought stress to cuttings. It’s good to water the soil or other medium before planting cuttings and keep it evenly moist while cuttings are rooting and growing new shoots.
Here are the most widely used rooting media:
Water: The good news is that roots grow fast in order to survive. The bad news is that leaving cuttings in water longer than 1 – 2 weeks promotes rot because the lack of aeration.
Sand: fine sand should be used to retain some moisture around the cutting and will also allow free draining. The sand should be cleaned and sterilized before use. Note: Seashore sand is high in salt concentration and is toxic to many plants.
Soil: Well aerated sandy soil is best. Due to the possible presence of root-borne disease, soil may need to be sterilized.
Peat moss: When added together with other materials increases the water holding capacity.
Coconut husk: Called Cocopeat, is often used in propagation and has the same use as peat moss.
Commercially made material such as Vermiculite, Perlite and Pumice can be used separately or in combination with other rooting medias. Using these reduces the weight of the planted container, they are clean and have high water holding capacity.
many plant varieties are propagated by stem cuttings. Most can be taken at any time of the year, but stem cuttings of many woody plants must be taken in the fall or in the dormant season.
Tip cuttings: Detach a 2 to 6-inch piece of stem, including the terminal bud. Cut the stem just below a node. Take away all lower leaves that would be growing below the soil or medium. Dip the stem in rooting hormone if desired. Gently tap the end of the cutting to remove excess hormone. Insert the cutting deeply enough into the media to support itself. At least one node must be below the surface.
Medial cuttings: To make a Medial cutting, do the first cut just above a node, and the second cut right above a node 2 to 6 inches down the stem. Dip in Rooting Hormone and put it in the cutting soil just like in tip cutting. Be sure it’s right side up. Place Axial above leaves.
Cane cuttings: Cut cane stems into pieces having one or two eyes, or nodes. The term “eye” refers to the node. Dust ends with fungicide or activated charcoal and dry several hours. Lay horizontally with about half of the cutting below the soil or media surface, eye facing upward. Cane cuttings are best potted when roots and new shoots appear.
Leaf cuttings, with no stems are used almost exclusively for a few indoor plants. Leaves of most plants will either produce a few roots but no plant, or just decay.
Whole leaf cuttings with petiole: Detach the leaf and up to 1 ½ inches of petiole. Insert the lower end of the petiole into the soil or medium. The new plant will grow at the bottom of the petiole. The leaf may be severed from the new plants when they have their own roots, and the petiole reused.
Leaf sections: This method is frequently used with sword plant and fibrous rooted begonias. Cut begonia leaves into wedges with at least one vein. Lay leaves flat on the medium. A new plant will arise at the vein. Cut sword plant leaves into 2-inch pieces. If you always make the lower cut slanted and the upper cut straight you will always be able to tell which is the top. Plant the cutting vertically. Roots will grow fairly soon, and sooner or later a new plant will appear at the bottom of the cutting. As with all succulent cuttings they will rot if kept too moist.