When you took home your Dieffenbachia, it looked like the perfect tabletop plant: a short, bushy profusion of gorgeous leaves. Then it started to grow. Now it’s grown a tall, skinny stalk that’s teetering under the weight of its foliage. What happened? We’ll explain what causes a leggy Dieffenbachia and what you can do about it.
The main reason for an overly tall and slender Dieffenbachia is a lack of sun. Moving the plant to a better-lit spot should help it grow normally in the future, though it won’t undo the legginess that’s already developed. If you prefer a smaller plant, you can cut the top portion off and root it in a new pot.
Keep in mind that it’s normal for a Dieffenbachia to eventually grow a tall central stalk – it’s not uncommon for these plants to reach 6 feet or more in height! This isn’t a problem unless the trunk and the leaves are undernourished. If you prefer to limit your Dumb Cane to a more manageable height, you can periodically cut or pinch off the foliage at the very top of the stem.
But I Thought Dieffenbachia Was a Shade Plant!
Dieffenbachia is more shade-tolerant than a sunflower or a tomato plant, but that doesn’t mean it will be happy if you tuck it away in a dim corner. These plants prefer bright, indirect light. They like a healthy amount of illumination even if they don’t want the sun smacking them right in the face.
A Dieffenbachia that’s not getting enough light will become etiolated. That’s the scientific term for the “leggy” look – a long, skinny stem with sparse foliage that’s mostly clustered near the top. The leaves might also become pale, thin, and elongated, and spaced far apart.
Plants do this in order to push upward past obstacles that are blocking out the sun. But that won’t help your Dieffenbachia if you’re keeping it in an overly dark room. It will just continue to shoot up until its floppy stem can no longer support its leaves.
Lighting Tips to Prevent a Leggy Dumb Cane
As you may have guessed, the way to avoid this problem is to choose a location with adequate lighting.
The spot you’ve chosen is bright enough for your Dieffenbachia if you can read without turning on a light (no cheating and using a large-print book). Look at the shadows, too – if they’re strong and dark, with sharply defined outlines, the sunlight is probably too direct for a Dumb Cane. Try to pick a spot where the shadows are a bit weaker, and their edges are slightly blurred.
North-facing windows won’t risk sunburn, but may be too dim. Eastern windows are often perfect because they only receive direct light during the coolest part of the day, when your Dieffenbachia can handle a few rays. A southern or western exposure will probably be bright enough, but you’ll want to keep your Dumb Cane 4-6 feet away from the closest window so it won’t burn.
Grow lights can also help in a pinch. Use the kind with LED bulbs, since they don’t give off much heat and won’t fry your Dumb Cane. Our usual recommendation is the effective but inexpensive Sansi 15W LED Bulb. See our article on grow lights for more detailed info.
Guiding Your Dieffenbachia’s Growth
There are a couple of other handy tricks that can help nudge your Dumb Cane to grow into the shape you prefer.
Number 1: Shake it up every once in a while. Being stirred by the wind is part of what encourages wild Dieffenbachias to grow thick stems. By providing a simulated version of this motion, you can help your plant develop a sturdy trunk, making it less likely that you’ll need a stake to prop it up as it gets taller.
Don’t go overboard – gently rocking the plant back and forth for a few minutes every couple of days is enough. Even lightly stroking the plant’s trunk or agitating it with a fan will promote healthier growth.
Number 2: Trim the top periodically. As we mentioned, Dieffenbachias tend to grow into a tall cane shape even if they don’t get leggy. If you prefer to keep your plant compact and bushy, you can make a habit of pinching or lopping off the new foliage as it emerges from the top of the stalk. This will steer your Dumb Cane toward growing out rather than up.
Fixing a Leggy Dieffenbachia
What if you already have a leggy Dumb Cane? Is there anything you can do to restore its former bushy beauty?
Sadly, even after you move your plant into better lighting conditions, the stretched-out portion of its trunk will stay that way. To correct it, you’ll have to cut your Dieffenbachia back down to size. Don’t worry; the plant should survive the operation as long as you prepare properly and take good care of it afterward.
- A sturdy set of pruning shears or a sharp knife.
- Some garden gloves – the sap from a Dumb Cane can irritate your skin.
- Potting mix with good drainage. Try blending 1 part African Violet soil, 1 part coarse perlite, 1 part coconut coir, and 1 part orchid bark chips.
- A pot with drainage holes.
- A disinfectant solution for your cutting tool. 1 part bleach to 9 parts water works well, as does ordinary rubbing alcohol.
- Optional: some rooting hormone to encourage your cutting to grow.
After wiping your shears down with your disinfectant, slice through the stem at a 45-degree angle near the top. Make your cut just below a node – these are the brown, slightly thicker bands along the stalk. It’s up to you exactly how much stem you want, but take at least an inch or two, because you’ll have to bury part of the cutting so that it stays upright.
If you’re using rooting hormone, dip the bottom end of the cut stalk into the powder or gel. Then plant your cutting in its new pot, deep enough that it won’t tip over.
You can repeat the process described above to get several cuttings from a single existing stem. This is a tried-and-true method of propagating a Dieffenbachia to produce new plants. Even segments without any leaves will eventually produce foliage, as long as each cutting includes at least one node. For more information on reproducing your Dieffenbachia via cuttings, read this article.
And if you continue to water and care for the original stalk, it will start sending out new growth from the uppermost node and become a healthy plant once again. If you prefer your Dieffenbachia on the shrubby side, you might want to cut it back to just above the soil.
Caring For Your Dieffenbachia Cutting(s)
It will take between 4 and 8 weeks for your new, shorter Dumb Canes to take root and start putting out new leaves. During that time, go easy on the watering, keep your plants out of direct sunlight, and make sure they get lots of humidity. If you’re worried the air is too dry, you can pop a plastic bag or some other transparent covering over the top of each cutting to help lock in moisture.
Another alternate method involves placing the stem sections in water first, then moving them into the potting mix after they’ve grown roots an inch or so long. This practice reduces the risk of the cuttings drying out, but it may take them a bit longer to get established when you transfer them to the soil. If you’re going this route, make sure each segment is at least 4-6 inches long, and replace the water every few days.
Air Layering Your Dieffenbachia
You can prepare your Dumb Cane for its haircut using a process called air layering, which encourages the plant to begin growing roots from its stem ahead of time. This will make it much easier for the cutting to dig into its new pot once you transplant it.
Identify the place where you’re planning to slice through your Dieffenbachia and make a preliminary cut about halfway through the stalk at an upward angle. Don’t forget to disinfect your knife first! Prop open this cut by sliding a toothpick or something of similar thickness into the gap.
Next, pack a moist, water-retentive growing medium around the opening. Sphagnum moss is the usual recommendation, but coconut coir also works well. Before applying your chosen substrate, make sure it’s saturated but not dripping – give it a good squeeze to get the excess liquid out.
Seal the substrate in with plastic wrap, securing the upper and lower ends with rubber bands, twine, zip ties, or duct tape.
Soon, your Dumb Cane will start to send out roots into the moss. After 3-6 weeks, they should be long enough for transplantation. Cut the rooted stem segments as described above.
Now that you have a better understanding of your Dieffenbachia’s growth habits, you should find it much easier to keep it from developing an unattractive, stretched-out appearance. And if your plant has already gotten leggy, you know how to correct it.
Don’t worry about harming your Dumb Cane by cutting it. These plants are survivors! Follow the steps above, and you’ll have your Dieffenbachia looking as healthy and sturdy as the day you first laid eyes on it.