The Plant Lady: Skip the seeds and cut into your plants’ growth potential

Spring is the perfect time to make softwood cuttings as plants are pushing out new growth.

Why make cuttings? There are multiple reasons. A cutting is a genetic clone of its parent plant, so there are no surprises as far as looks and growth pattern. At the UC Davis Botanical Conservatory, we do a lot of cuttings simply because we lack seed from many plants due to various reasons, such as lack of pollinators or no male/female plant. Furthermore, taking cuttings is a fast and reliable method of obtaining numerous plants from a small amount of source material.

Before going into the step-by-step procedure to successfully take a cutting, let’s first look into the primary hormone for root production, auxin. It is primarily produced in the active growing plant tips (apical meristems) and is actively transported downward along the gravity gradient towards the roots – an effect known as gravitropism.

The rooting hormone sold at nurseries is a synthetic form of auxin and is commonly used when taking cuttings. A rooting hormone is not always needed; I am using it less often at the conservatory. I have found if we take the most actively growing part of the plant (where there is generally enough Auxin), then the plant has no problem developing roots. The woodier the cutting (i.e. less-active growth), the more hormone is needed. When you take a cutting you are forcing the auxin to pool at the cutting location and thus roots are formed.

Tips for softwood cuttings

▪ Begin with a pot which has drain holes. Fill to the top with a cutting media – this can vary from perlite, peat moss to sand. My go-to mix for years has been a 50/50 blend of vermiculite and perlite. Small bags can be found at most nurseries. For succulents, pumice or red lava rock is ideal. Thoroughly wet the media.

▪ A cutting needs to be a section of stem with at least two nodes (the junction where leaves or stems grow out of). At least one node needs to be below the planting media and at least one needs to be above. I generally make cuttings which are about a 4-to-8-inch section of stem. A semi or softwood cutting is the newest growth, which is best to target for cuttings. A good test to identify “new growth” is it should bend slightly. Keep in mind that not just the plant tips can be used for cuttings – multiple cuttings can be taken from along one stem. The woodier or firmer the stem, the higher the requirement for rooting hormone.

▪ Cut directly below the node that is to be buried. Strip all leaves off the stem up to the point to which it will be buried. Then, bury the cutting deep enough so that it stays upright.

▪ Cuttings should be placed in the planting media as soon as they are taken from the mother plant. However, if you cannot pot up your cuttings quickly, wrap them in a wet paper towel and keep them in the fridge. When I worked at a wholesale nursery, we would get cuttings shipped to us in this fashion from South America. Succulents, however, should not be planted right away. They need time to callus and heal over. This can take anywhere from a day to weeks. During that time period, keep them in a cool dry place, placed upright to keep auxin pooling at the bottom of the plant.

▪ All flowers, buds and fruit need to be removed, as they are an energy sink and you want all energy to go to root formation. Even large leaves can be cut in half.

▪ If rooting hormone is being used, dab the cut stem into the powder. A little bit is all that is needed.

▪ Multiple cuttings can go into one pot as they are not competing for root space, water or nutrients. Assume that not all cuttings will survive, so make multiples.

▪ It is key to put the pot of cuttings into a humid environment as quickly as possible as they are losing water through the leaves. Most people do not have a mist bench, so place your pot in a sealed plastic bag. Place out of direct sunlight. Condensation should be on the walls of the bag, but not so much that it runs down. If water is running down the sides, open the bag to vent for a time. An alternative is to mist the cuttings periodically throughout the day. Do not fret if leaves fall off. This does not mean your cutting has died. Succulents should not be put in plastic but, instead, periodically watered.

▪ When numerous roots form, it is the appropriate time to plant each cutting into its own pot filled with potting soil. Depending on the plant, this time could range from a few weeks up to six months. Look for roots growing out the bottom of the pot or tug gently. If there is resistance when tugging then you know adequate roots have formed. Careful though, you don’t want to tug to harsh or you run the risk of ripping off roots.