Using a rooting hormone to propagate plant cuttings increases the chance that the new plant will thrive. Taking a cutting from a plant and growing it produces a new plant identical to the parent plant. This is a reliable and inexpensive way to propagate your favorite plants and the best way to grow new difficult-to-propagate plants. Stem cuttings are the most common, but plants can also be grown from root cuttings and leaf cuttings.
What Is Rooting Hormone?
Rooting hormone products are chemicals that stimulate root growth, typically on plant cuttings. They generally come in powder, gel, or liquid forms.
When the rooting hormone is used correctly, it causes the cutting to develop roots quickly and be more robust than cuttings that don't receive the rooting hormone. Most homeowners use it primarily on ornamental plants in the landscape and to propagate succulents. It is available at garden supply stores and at online gardening sites.
Which Cuttings Can You Use?
The rooting hormone works on a variety of cuttings, including new growth, woody stems, leaves, and roots to dramatically increase the odds of success with propagation. If the plant is a blooming plant, wait until the blooms fade before taking the cutting. Rooting new plants from parents requires patience and the cuttings are fragile before the root system develops. In general, keep the planting medium moist but not wet and provide light but no direct sun.
Using Rooting Hormone on a Stem Cutting
Remove a fresh, healthy stem cutting from a parent plant using a clean knife or shears. Use only cuttings from vigorous and healthy plants, and make sure the growing tip is between three and eight inches long. Cut the topmost few inches from the stem. The cut should be made near a node, which is a slightly swollen knob on the stem. Remove any leaves or flowers from the node area.
Moisten the bottom few inches of the cutting so the rooting hormone will adhere to it.
Pour a little rooting hormone out of the container and dip or roll the bottom few inches of the cutting in the rooting powder. Do not dip the cutting directly into the rooting hormone container. Don't apply the powder any higher than the planting depth. Shake the excess powder off by lightly tapping the cutting against the edge of the container.
Plant the cutting in a soilless potting medium. Make a hole in the potting medium with a pencil or similar tool. Make sure the planting hole is wide enough that the rooting hormone is not rubbed off as you sink the cutting into the soil.
Tamp down the soil around the cutting to remove any air pockets. Water lightly and keep the cutting warm at 60 F or higher. Most plants root better if they are kept out of direct sunlight.
Working With Leaf Cuttings
Some plants, such as many succulents, don't have stems. These plants can be propagated by leaf cuttings. Depending on the leaf structure, apply the rooting hormone to the part of the leaf that was closest to the center of the plant and cover it with a soilless potting mix. Plant the leaf partway in the mix. If the leaf has a short stem, such as found in African violets, dip the stem in rooting hormone and plant it in the potting soil just like you do with stem cuttings, sinking the stem up to the leaf in the mix.
In some cases, it is necessary to cover the backside of the leaves with the rooting hormone and lay them on top of the moist soilless mix and lightly press down until the leaf touches the mix. Keep all rooting plants out of the direct sun until they have developed a robust root system.
Working With Root Cuttings
Root cuttings are just what they sound like. They are pieces of the root of a parent plant that will eventually produce a new plant. Pull the soil back from the root area of the parent plant. Cut 2-inch pieces of slender roots and recover the root area of the parent plant. Roll the root cuttings in the rooting hormone and plant them shallowly in a rooting medium. Keep the medium moist but not wet. Root cuttings are frequently taken in the fall to give the plant the entire winter to produce a new plant by spring.