Rooting plants to propagate them is a good example of the old adage that says there is more than one way to skin a cat. Like many such sayings, it creates an ugly image like the vision of a cradle falling when the bough breaks, yet has merit for its sentiment. There are numerous plant parts that will root, depending on the species, and some seem to root from anywhere to make your task easier. Let’s start at the top, with tip cuttings. The newest growth on a plant resides at the end its branches and stems. This is where the action is for many rooting efforts, since the tip is a hive of active growth.
While it is possible to root some stems by taking a literal tip cutting with barely any stem attached, cuttings made a few inches behind the tip usually root better. (In this case, ‘better’ means faster, in higher percentages, and with stronger roots.) For example, many shrubs will root from summer (aka semi hard) wood cuttings that are 4-6 inches long. That size enables you to strip the leaves off of the lower half to bury the stem deeply and still keep some leaves on top so the essential process of photosynthesis can continue. When you make the cutting further behind the tip and do not include it, you make a stem cutting. This part of the plant will root because stems have structures called nodes. Some plants, like trailing philodendron, drop roots easily when they come in contact with soil or bark, allowing them to climb. Others must be coaxed. To locate the nodes, look for markings along the stem, often found where leaves are attached. That growth is your clue that a viable node exists and may root. When cut into sections with at least one node present, stems can be laid down in the rooting media or stood up in it, depending on how supple they are. Perhaps the most common examples of commonly-taken stem cuttings besides the aforementioned vines are plants with canes such as bamboos, dumb canes (Dieffenbachia), and some begonias. Their leaves will wilt quickly so stem cuttings are not so successful. To root, canes need only one node, usually marked by a circle on the stem, and an inch or so of stem on either side. That means one naked cane can produce multiple plants, as I am hoping will happen for the sad Ti plant I am trying to save.
Root cuttings are more trouble to take than a simple tip snip, but are a tried-and-true way to propagate many woody plants. Spireas and other thin-stemmed shrubs can be difficult to root from skinny stem or tip cuttings. Instead, dig under the soil and take root cuttings about as big around as your index finger and 3-4 inches long. Thanks to the natural ability of plant cells to differentiate and become any necessary plant part, the root can grow roots and then sprout stems, leaves, and flowers. This quality also explains how tissue culture propagation works, but that is a topic for another day.
Less common but equally effective when appropriate are leaf cuttings. You’ll see this plant part used when no stem exists, such as you find in Gesneriads including African violet and gloxinia. In these cases, one stem with a leaf attached can produce a dozen tiny plants when the stem is plunged into the rooting media up to the leaf. They emerge at the growing point where stem and leaf connect. If no stem is available, an entire leaf can be scored with a sharp blade, laid on the rooting media, and misted to maintain moisture levels until plants sprout from the cut surfaces. To cut is to wound, and the natural tendency of a wounded organism is to do what is necessary to survive. When propagation occurs, it is because of the plant’s innate response to the wound even if we would like to think the plant wills itself to create future generations to sustain the environment. If that were so, propagation outcomes would be predictable but they are not. Depending on what kind of cutting you make, a liquid or powder Hormex product can be your best ally in the process. Choose the appropriate formulation of powdered Hormex for woody plant cuttings taken from tips and stems, and use liquid Hormex for beds of root cuttings and canes laid sideways in a flat or pot. Green plant cuttings of any sort can be dipped in powder or soaked in liquid Hormex or watered with it.
To summarize the dilemma of what kind of cutting to take, remember this: if the tip wilts, try the stem. To paraphrase another of those old saws, if at first you don’t succeed, try, try again – but take cuttings from a different plant part. Be persistent and know that patience is truly a hard-won but valuable virtue, especially in plant propagation.
Nellie Neal is a passionate propagator and owner of GardenMama, Inc. She advocates for gardening 24/7 at her website, www.gardenmama.com. Ask questions and comment about this blog on the Contact Us page of www.hormex.com.