Propagation
Scrabbly, tenacious, generous
Houseplants are scrabbly, tenacious, generous things. One of the most popular pieces I’ve ever written for this newsletter, which is nominally the chronicle of a school gardening program, was about how to care for them. It’s only a tangentially related subject but, especially here in the Northeast, those of us who love green and growing things start needing something to do by mid-January, when the romance of fallowness is gone and we start to fantasize about snowdrops and turned soil.
And though it might seem counterintuitive, January is a fine time to try your hand at propagating houseplants if you’ve never done so. All you’ll need is a few water glasses, a clean paring knife, and a windowsill or ledge that gets indirect sun—I find that east or west-facing is good, because that orientation will keep the tender plants from being blasted by the full, desiccating salvo of southern light before they’re ready for it.
The kind of propagation we’re talking about here is done hydroponically—that is, in water—rather than in soil. Not only is this method tidier, but it requires no rooting hormone and produces very satisfactory results for me a good portion of the time. Before you try, sit down for a minute and examine the plant you want to propagate. Consider its condition, its beauties, its lot in life. Just like us, it wants to eat. But, unlike us, it can’t amble over to the fridge at midnight if it gets hungry. Because plants lack this mobility, they’re gifted with different adaptations—most notably, the ability to transform parts of themselves to become nutrient receptors by suddenly developing roots. If we can remove a part of a plant and trick it into rooting for us, we can eventually pot that rooted cutting in the soil and, over time, have ourselves a new specimen.
Today I’ll discuss two ways of pulling off this wonderful magic trick of multiplication. The first is to take cuttings below nodes and place them in clean water. To do this, examine the houseplant you want more of to find leafy shoots—never shoots with flowers—that bear one or more small bumps. These are commonly called “nodes,” and are the locations below which roots will emerge from a successful cutting. I’ve highlighted two such nodes on a Satin Pothos of mine in the very fancy and technologically advanced photo below:
Ideally, you’ll take a clean paring knife to a branch with only one or two leaves at the end and cut it off horizontally just below a node. If you take a cutting from a section of the plant without any nodes, it might stay healthy and happy in water for quite a while, but will never send out any roots. Remove all but one of the leaves from the cutting using that same knife, then place it in a glass or vial of clean water, leaving it on a bright windowsill.
You’ll want to take more than one cutting, because there’s no guarantee of success. Like summer storms or teenage love, cuttings cannot be controlled—sometimes things will go well, and sometimes there will be thunder. Even after years of doing this, my success rate hovers around 60%, a modest turnover I’m quite happy with, since I tend to take batches of ten to twelve cuttings at a time.
Keep an eye on the water in your glass to make sure it doesn’t get scummy or moldy, switching out the water or, in the dirtiest cases, the glass once every week or so. Over time, the successful ones will develop roots, as in the picture below:
You’ll notice that its sister never made it and that I stopped topping up the water once I realized the roots weren’t coming. C’est la vie. Or, rather, c’est la mort. Simply get rid of the failures and, once the successes have developed strong roots like the one pictured above, transfer them to a small vessel—it can be a terra cotta pot or even a coffee mug—full of well-draining potting soil and water it gently in. Voila.
Yet some popular houseplants, like the nearly ubiquitous Swiss Cheese Plant (Monstera adansonii) sometimes don’t produce nodes on their shoots. What shall we do if we want more of these? Well, I’m happy to tell you that success here is even easier to achieve. The solution is to lift the whole root system out of the soil, hack off a rooted section of the plant with a clean trowel, and either pot it into water as in the method above until it develops stronger roots, or plop it straight into a container full of soil. This method, called division, won’t work with plants that grow a central taproot but, for the many types of houseplants that grow in your typical coiled and matted snarl, it works just fine. The Monstera pictured below was propagated this way—you can see the leaf from the original cutting balled up in the background like a fist and, in the foreground, the fresh new leaf it produced after two weeks rooting in a glass of clean water.
There are, of course, more types of houseplants and more methods gardeners have developed to multiply them. But it’s a wise policy to begin with simplicity, and these simple strategies will take you quite far. The propagation station near my classroom window has become a factory where I produce new plants to give away to other teachers, and those little gifts are always received with far more delight than I’d expect. There’s nothing quite as encouraging as a glimpse of green in winter.