THE WASHINGTON POST – About two years ago, the pandemic pushed people into their homes – and sent houseplant sales soaring. New houseplant owners might hesitate to expand their collection beyond those monsteras and philodendrons they bought in 2020.
Plants can be expensive, and growing from seed is time-consuming. But there is an easier, cheaper way to grow new houseplants: propagation, or the process of growing a new plant from a piece of a mature one.
You can propagate with seeds or roots, but the easiest and most common method is by cutting, or transferring a piece of a mature plant into water or soil and letting it grow a new root system.
Propagating with cuttings offers a lesson in plant biology. Landscape and greenhouse field specialist at the University of New Hampshire Extension Emma Erler said every plant has a meristem, a type of tissue that contains cells that can develop into different plant parts.
“Above ground, meristematic tissue can turn into buds and shoots, but it’s also capable of turning into roots,” Erler said.
There’s also a sentimental factor to propagation. “You grow a plant under your care, take a cutting and then pass it on to someone else,” said shop director Mollie Lee at Little Leaf in DC, which sells cuttings for propagation.
Here’s how to use cuttings to reproduce your own plants at home, according to plant experts.
CHOOSE A PLANT
According to plant stylist and consultant and the founder of Greene Piece Maryah Greene, cutting works on many common, easy-to-care-for houseplants, such as pothos, monsteras, philodendrons, snake plants and ZZ plants.
But different plants require different methods of cutting, said plant education coordinator at the Sill Paris Lalicata. For example, pothos, monsteras and philodendrons can grow roots from their stems. You can also propagate plants that don’t have stems, such as snake plants, by cutting from their leaves. Propagation usually works best when you cut from a mature, healthy plant with new growth. Erler suggested choosing one that needs pruning.
(You can often tell when it’s time, because a plant will look fuller on one side or appear unkempt.) That way, you are improving the parent plant’s health and growing a new one atthe same time.
Stem cuttings grow from aerial roots, or roots that grow above the soil on the stem of a plant.
To reproduce with a stem cutting, Lalicata suggested choosing a healthy-looking area with a few leaves growing from it. Successful cuttings are usually about four to six inches long.
Next, find a node, the nub that connects a leaf to a stem. “Nodes are a plant’s growth points, and in them are hormones that promote growth if you put it in soil or water,” said co-founder of the plant delivery service Plant Proper Matt Aulton.
Use a clean pair of pruners to cut about a quarter-inch below the node at a 45-degree angle. If you only have kitchen scissors, Lalicata suggested sterilising them with hot, soapy water or rubbing alcohol to avoid spreading pathogens that could harm your cutting.
Remove all but one leaf from the cutting to increase its chance of rooting. “Too many leaves can cause the plant to focus its energy on keeping them alive,” Lalicata said.
Choose a vessel to propagate your cutting in, such as an old jar or small vase. Many plant stores sell test tubes, so you can create a propagation station. The most important thing is to use a vessel with a narrow top to support the cutting.
Next, Greene said, fill the vessel with just enough water to avoid getting the leaf wet. Tap water is fine, but Lalicata said it should be at room temperature to avoid shocking the plant. Once your cutting is in water, place it near a bright – but filtered – window, because too much direct light could harm the plant, Erler said. “Cuttings don’t have roots yet to take up water, so if it was in a really warm, sunny spot, that cutting might lose water really quickly and dehydrate,” she said.
According to Lalicata, stem cuttings can root in a few weeks. While you wait, change the water weekly. If the cutting is black or slimy at the base of the stem, Lalicata said, it could be rotting, which means you’ll probably have to start over. If you notice rotting below the root growth, simply cut the slimy part off.
Propagating from a leaf uses a different cutting process, and these plants take longer to root. Lalicata said it may be a few months before you see progress.
On a snake plant, she suggested cutting horizontally at the bottom of a leaf, as close to the soil as possible. You can use just the top few inches of the leaf, or you can segment it into multiple cuttings. To propagate a ZZ plant, cut off a healthy-looking leaf as close to the plant’s stalk as you can.
After you make the cut, Erler suggested leaving it to dry for a full day, so the cut surface can form a dry, crusty layer. “Allowing the cutting to callus over prevents root rot, and rooting is more likely with this approach,” she said. Putting liquid or powdered plant growth hormones, available at greenhouses, on the bottom can quicken the process.
Follow the same steps as you would with stems to propagate succulents in water.
For a snake plant, Lalicata said, immerse the bottom third of the leaf; for ZZ plants, submerge just the bottom tip of the leaf.
Erler prefers planting leaf cuttings in a standard indoor soil mix as soon as you cut them, because she said they can easily rot in water. If you’re planting an unrooted cutting, she recommended watering the soil and using your finger or a pencil to create a small hole.
Gently place the cutting inside. You’ll need to go a little deeper to plant arooted cutting.
If the plant doesn’t stand up straight on its own, Aulton suggested stabilising it with a bamboo stake; over time, the roots should hold the plant up.
TRANSFERRING A CUTTING TO A POT
Once the roots are two to three inches long, you can transfer your cutting to a small pot with soil, where it should eventually grow deeper roots and more leaves.
Whether you put a fresh or rooted cutting in a pot, Aulton recommended choosing a two- to four-inch pot with drainage holes to prevent root rot. Erler suggested adding enough soil to get close to the top of the pot, with about a quarter-inch to spare.
Then you should gently pat the soil down. As your cutting grows, you’ll need to water it more than you would a mature plant; Erler suggested keeping the soil moist for the first week to wean the cutting from the water it had been immersed in. After that initial period, wait for the soil to dry completely before you water again.