by Evin Morrison, Extension Master Gardener
Photos © Evin Morrison
If you’ve fallen in love with houseplants, the best kept secret is that once you have them you can basically make as many as you want. There’s no need to rush back to the store and buy more as long as you’re willing to give the ones you already own a trim.
Propagation is the practice of dividing or cutting a “parent” plant into smaller pieces to create even more plants. Many gardeners fill their flower beds by dividing perennials, or by taking cuttings from woody plants like roses. The same principle applies to your houseplants.
Whether you want to create a whole new plant to grow on its own or need to fill in the gaps of a sparse plant, propagating is an affordable way to build on the collection you have. Plus, it’s an opportunity to experiment with indoor gardening, get up close and personal to the plants that normally just sit on a shelf, and it’s a lot of fun.
There are many ways that you can propagate plants. Most people find a way that they prefer, but no matter what you read on the Internet, there’s no wrong way to grow. Some plants will react better to certain methods, but give yourself a chance to try a few and see which one works best for you, your plants, and the environment you can provide.
Water Propagations
By far one of the most common ways to propagate a plant is to cut a piece off that includes a node and stick it in fresh water. It really is that easy. However, to increase your success rate there are a few things to keep in mind. The most important when taking a cutting is to make a clean cut right below the node of the plant. The node is usually identified as the swollen section of a stem. It’s often the part of a plant from which the leaf emerges. This swollen section is the part that will also grow new roots and needs to be under water.
Taking a clean cutting is important, because it ensures that no bacteria is being submerged into the water alongside the plant. Additionally, you will want to make sure to remove excess stem below the node and any leaves that might be submerged. Those pieces will only lead to rot and can put the success of your propagation at risk.
The other thing to remember when water propagating is to change the water frequently. If the water is left stagnant, there’s a good chance that it will start to grow algae and start to smell. Algae will quickly consume the available oxygen in the water leaving nothing for your plant to use as it grows roots. Aim to change the water weekly at the very least.
Also, monitor the water level, if you are keeping your plant starts in a sunny location, and watch for evaporation. Keep the water topped off so that the node and the new delicate roots stay submerged the whole time. Now that things are heating up outside, also make sure that any propagations near sunny windows aren’t getting too hot. The white roots that appear in the water are very delicate, and hot water will surely cook them.
While getting a plant to root in water is easy, the harder part comes with potting it into soil. Once your plant is well-rooted, maybe it’s even produced a new leaf, you can pot it like any new houseplant in the potting soil you prefer. Make sure to keep it well watered until you see more growth, or you risk losing all your hard work. The roots that are produced in water are only adapted to that environment. Keep the soil on the moist side, and those roots will be able to continue to thrive while the plant sends out even more roots that are able to take up nutrients from the soil.
Terrarium Propagations
When hunting the Internet for “propagating houseplants,” often you will find pictures of water propagations, but the truth is that propagating in a terrarium might be even easier. If you have a large jar or enclosed glass or plastic container, you have a propagating vessel. For small cuttings you can even reuse a takeout container that has a plastic lid.
For this method, all you need to do is fill the bottom of the jar with a few inches of substrate. Try a mix of coco coir and LECA (lightweight expanded clay aggregate). They will hold moisture, and plants will root into this mixture readily. Sphagnum moss is also a great option, but try to find a brand that is sustainably harvested, as sphagnum and peat moss are nonrenewable resources. Using eco-friendlier resources like coir and LECA (which can be rinsed and reused), helps us gardeners protect the planet we love.
Once your base is laid, moisten the mixture. You want the base to be wetter than you are used to when watering your houseplants, but not floating in water. This way the water will circulate and create a humid environment perfect for encouraging new growth. You can either stand up your cuttings in the substrate, or lay them across the top. The key is to make sure that there is contact between the node and the base layer, so the roots can take hold and grow. Now just close the terrarium and set it in a bright space. You should see condensation build up and then dissipate throughout the day. If your container is always covered in condensation, remove the lid for a little bit to release some of the excess moisture. This will keep things from rotting. Since the plants’ roots are already used to growing in a substrate, potting them is much easier. You will still want to transition the plants slowly from a super humid environment to your living room space, but you won’t need to be as diligent about protecting the new roots as you are with water propagation.
Soil Propagations
Some plants, especially succulents, do well being propagated directly into soil.
Many people who want to make their plants look fuller simply trim below a node and push the fresh cutting into the substrate. This works quite well for plants like pothos and trailing philodendron that often grow long but can start to look scraggly around the base. The trick is making sure that you don’t let the plant dry out too much. Fresh cuttings need moisture to root, so if you are good about sticking to a watering schedule this mode of propagation will most likely work for you.
For succulents, finding a piece to root is a little different, because you have more options. While many of them propagate readily from stem cuttings, you can also propagate most varieties from the leaves. To propagate from a leaf, it’s important to get a good specimen to root. Grab the leaf by the base and gently wiggle. Usually, it will break away quite easily. The key is to make sure that you get a clean break. Torn succulent leaves will not root. Now take the leaves and, using a flat tray or an extra saucer from a terra-cotta planter filled with cactus mix, lay them across the top. For more curved varieties, gently press the base of the leaf down to make contact with the soil. Use a mister, and every few days mist the top of the soil and the leaves, but make sure that you aren’t keeping the soil too wet.
Before you know it, roots will begin to appear. If the roots are sticking out into the air, you can gently stand the leaf up more, so the roots make their way down into the soil. Unlike tropical plants, which you can pot as soon as you see healthy roots, with succulents you’re going to wait longer. Once roots form and grow strong enough to support a new plant, you’ll notice a very tiny version of the parent plant begin to emerge. Leave the original leaf alone and continue to mist your tiny new plant as needed. The original leaf will eventually shrivel as the new plant uses it as a source of energy. At this point, you can remove the dead leaf, which should break away easily. In fact, if there’s any tension, leave it connected. From one leaf you get a whole new plant that should look identical to the original!
Creating more plants is a fun way to share your hobby. Always propagate a few pieces of the plant that you are trying to grow as an insurance policy to make sure that you have at least one successful rooting. If they all work, you can pot them and gift them to your friends and family. It’s fun to see a plant in someone else’s home that you started from a tiny piece of stem.
Happy propagating!