There are multiple ways for plants to promote their own survival and survival of future generations. Seed dispersal is one of the more common ways, but some plants can create new life from just a single leaf. This process of reproducing and creating new plants is called propagation. Seed propagation is a form of sexual reproduction but asexual reproduction is preferred for some plant varieties.
Propagation by cuttings is a form of asexual, or vegetative, propagation. This method involves a section of a plant that has been removed from the mother plant. This type of propagation is a favorable choice because it can be a faster way of reaching plant maturity. Additionally, vegetative propagation creates a genetic duplicate of the mother plant whereas seeds can create variation due to cross-pollination. However, vegetative propagation can fail if sterile equipment is not used and if the cuttings are not given proper growing conditions. Knowing which plants root easily via asexual reproduction is key.
Propagation by stem cuttings works well with many herbaceous annuals and perennials such as lavender (Lavandula angustifolia), coleus (Coleus spp.) and rosemary (Rosmarinus officinalis). Trim a cutting about 3 to 4-inches long off the end of a fleshly stem. While woody stems can be propagated, it may take longer and has a lower success rate. Dip the newly cut stem in rooting hormone and bury the cut end in soilless potting mix in a container. Roots should start developing within a couple of weeks.
Leaf cuttings works well for many varieties of succulents. Snap a healthy leaf off where it is attached to the mother plant. Succulents such as Echeveria and Sedum have leaves that are easy to remove without causing damage to the leaf or mother plant. They also root easily so they don’t require a rooting hormone. Push the end of the leaf that was attached to the stem into a loose potting soil. While the roots develop, a new “baby” plant will also grow at the base of the leaf on the soil surface.
Growing conditions for cuttings should be kept warm and humid. This can be done in a greenhouse setting or can be created by putting a clear plastic cover over the container. Keep the soil moist. Once roots begin to grow you can remove the cover.
Division is a form of propagation that works well for Irises (Iris spp.), Daylilies (Hemerocallis spp.), Bugleweed (Ajuga reptans) and others that produce new plants along the existing mother stock. The new plants can be separated from the mother plant and planted separately. As with any newly installed plantings, frequent watering is necessary as the plants become established.
Plant propagation allows for plenty of experimentation and discovery. It is easy to test the speed of rooting by comparing plants side by side with and without rooting hormone. Compare the rooting success rate with stem cuttings placed in water versus those placed in soil. After you develop your hypothesis and execute the experiment, see if you can determine why the results occurred as they did. Get the family involved by setting up multiple experiments allowing each person to claim their own hypothesis. The education will be fun but also productive as your plant supply increases.
Cynthia Domenghini is an instructor and coordinator for K-State’s horticultural therapy online certificate program.