The multiplication of plants, known as propagation, is an entertaining and rewarding part of gardening. Many people are familiar with growing and multiplying plants using seeds. This method is useful but can be time consuming and, depending on the plant, difficult.
Luckily, many plants can be reproduced from a cutting, a process known as asexual reproduction. With a cutting, you are certain to reproduce the plant exactly, whereas sexual reproduction is a roll of the genetic dice.
If you have never propagated from cuttings before, I recommend starting with succulents. Succulent cuttings need little encouragement to root and regrow. I have often found a broken piece of a succulent that has fallen into some hidden place, grown roots and re-established itself. But like their parent plants, they are sensitive to over-watering and fungal infections. There are, however, things you can do to minimize complications and help your cuttings grow.
First, choose a place to make your cut. If the plant is leafy, choose a spot with only one or two leaves above the incision site. These leaves will feed the plant through photosynthesis, but will also release water vapor. When necessary, remove excess leaves from the cutting.
If you are propagating something other than a succulent, look for new growth. This part of the plant is more adaptable than an older or woody area and will root more easily. You may need to wait for another season, when the plant begins fresh growth. Convincing a woody cutting to root can take weeks, or even months.
Use a sharp, sterile knife to make the cut. A dull blade can damage cells at the site, causing rot. An unclean knife can introduce fungi and bacteria and transmit diseases.
When propagating succulents, set the cutting aside for a day or more to let the wound callous. This will prevent any moisture, fungus or bacteria present from entering the cutting. If your incision site is narrow, consider making your cut at a sharp angle. This produces a larger wound, but also creates a larger root-growing area.
Prepare a small pot with well-drained soil. Some people prefer to use perlite, vermiculite or a mix of the two. I have the best luck with cactus soil mixed with a little extra perlite. This provides a stable and well-draining environment for the cuttings. Be gentle when placing your cuttings. Pressing them roughly into the medium will damage the wound site and invite the entry of unwelcome microscopic visitors.
You may wonder how this little snippet is supposed to grow. The answer is: plant hormones. Each plant leaf releases a specific hormone that flows downward, instructing the plant to grow new roots. In turn, each root sends a different hormone upward, demanding new leaves. When you take a cutting, you upset this balance. Hormones from the roots are literally cut off, leaving only those coming from the remaining leaves. It is this imbalance that causes cuttings to sprout roots.
You can increase this imbalance, and your chance of success, with rooting hormone. Available at nurseries and garden stores, rooting hormones are synthetic versions of those found within the plant. If you purchase powdered rooting hormone, dip the wound site in it before placing the cutting in the growing medium. If you purchase a liquid type, dilute it as directed and pour it into the growing medium after you have placed the cutting. I use the liquid form and add a little every time I water my cuttings.
Now comes the time for patience. Minimal watering and bright, indirect sun will be all your cutting needs to do its work. Resist the urge to check for roots. When roots first grow, they are only one cell thick and very fragile. You will not be able to see them, and fussing with your cuttings will break them.
Watch your new plants for signs of over- or under-watering and infection. If you suspect a fungal infection, reduce watering and spray the cutting with Neem oil. Rooting time varies, but I usually check mine after about two weeks. Using a thin tool, I push aside some of the growing medium and look for roots.
In the end, cuttings are like children. All you can do is give them the tools to succeed and hope for the best. If you are lucky, you will soon have some beautiful new additions to your garden.
Free talk on summer produce
The UC Master Gardeners of Napa County will give a free talk on “Unusual Varieties of Summer Fruits and Vegetables” on Thursday, Sept. 7, from 7-8 p.m. at the Napa Public Library, 580 Coombs Street, Napa. Learn what grows well in Napa County. Master Gardeners will show examples and talk about some of their favorite varieties and why they like them. Get some ideas about what to grow next year or to buy now at farmers markets. No reservations required.
Join the Master Gardeners
Do you want to become a UC Master Gardener of Napa County volunteer?
To obtain an application, you must attend an information meeting. For meeting dates, location and times, or to learn more about the program and volunteer commitment, visit the UC Master Gardener of Napa County website.