How to Grow the Dumb Cane Plant

Dieffenbachia is a tropical perennial genus that has several species that people commonly use as houseplants. They feature ovate, pointed leaves in a range of combinations of cream, green, and white. A very large dumb cane plant that is well taken care of can easily top 10 feet, and it’ll have leaves that are up to 20 inches long. However, it’s rare for this plant to reach these proportions when you grow them inside, and they tend to be around 3 to 5 feet tall.

The dumb cane plant is a fast-growing cultivar that can get up to two feet high in the first year when you plant a rooted cutting, as long as it gets enough light. The name for this plant has fallen out of favor in recent years as being a derogatory term, but it was originally called the dumb cane plant because it has toxins that cause slurred speech. It’s very toxic to cats, dogs, and humans, but it’s also very easy to grow as long as you keep it well out of reach. To figure out how to grow it, read on.

The Dumb Cane Plant is a very colorful houseplant that can introduce texture and color into your room.

Dumb Cane Plant – General Information

Botanical Name:	Dieffenbachia spp.
Common Names:	Dumb cane, dieffenbachia, leopard lily
Family:	Araceae
Hardiness Zones:	10 to 12
Mature Size:	3 to 10 feet tall and 2 to 3 feet wide
Native to:	South America, the Caribbean
Plant Type:	Perennial, herbaceous
Soil pH:	Acidic
Soil Type:	Well-drained
Sun Exposure:	Partial
Toxicity:	Toxic to pets and people

Dumb Cane Plant Cultivation and History

Plants that come from the Dieffenbachia genus are native to Central America, South America, and the Caribbean. They have also naturalized to Singapore, Sri Lanka, Samoa, Malaysia, and islands in the South Pacific, including Fiji and Hawaii.

The genus got its name from an Austrian botanist who was also the head of the Austrian Botanical Gardens. His name was Heinrich Wilhelm Schott, and he named it after his head gardener, Joseph Dieffenbach. It got the common name of the dumb cane plant due to the fact that it produces a bizarre affect if you ingest any part of the plant. It has calcium oxalate crystals in the stems, leaves, and roots.

If you happen to ingest it, it will prompt your body to release histamines, and this can result in throat and mouth swelling. In turn, it can cause breathing difficulties and lead to death in severe cases. Also, irritation to your throat and vocal cords can render the person who ate them mute. There have been cases where people needed tracheostomies to help them breathe after they ate part of the dumb cane plant. The oxalate crystals in this plant can be so powerful that touching your lips to the stem can cause swelling. The symptoms will start in minutes, and they can last for days.

It was originally used as a method of punishment for slaves in the Caribbean, and some slaves ate this plant as a way to commit suicide. In Brazil, this plant was rumored to cause sterility. Nazi SS leader Heinrich Himmier also suggested that they use extracts of the dumb cane plant to sterilize what they called “radically undesirable war prisoners.”

However, many cultures have used the dumb cane plant’s stem, roots, and leaves for centuries medicinally as a form of birth control and to treat inflammation, dropsy, sexual disfunction, and gout. It also became a very popular plant to use for home decor during the Victorian era.

There are currently 135 known species in this genus, but you won’t grow all of them as houseplants. The dumb cane plant species you’ll find most commonly grown as houseplants include D. ammonia, D. picta, D. bowmannii, and D. seguine. These plants range in size anywhere from 2 to 10 feet tall and two or three feet wide, depending on the cultivar you pick out. THe leaves come in an elliptic shape, and they can get up to 10 inches long. The leaf patterns can be mottled or solid green, and they can have patches or splotches of cream, white, or yellow. The patterns on the leaves are why many people call it the leopard lily.

If you grow the dumb cane plant indoors, it’ll rarely flower. If you get it under the right conditions, it can produce very pretty white flowers that look like calla lilies, and this isn’t surprising as they’re part of the same family. If you pollinate this plant, it’ll produce bright red berries. The leaves will slowly drop off to expose the stem, and this looks very similar to sugar cane. As the leaves start to fall and leave the top foliage on, it looks like a miniature palm tree.

Dumb Cane Plant Care

It’s a good idea to grow the dumb cane plant outside under indirect but bright sunlight. Plant it in a well-draining and fertile potting mix with a higher peat content. This is a tropical plant, so it thrives in areas that get higher humidity levels. You can increase the relative humidity by putting the container on top of a tray of pebbles and filling the tray with water. Misting the leaves can also help during dry weather.

Overwatering is very common with this plant, as is the case with many houseplants. Let the top two inches of soil dry out between watering so that the moisture drains away from the root system. If you wish, you can remove the weak, lower leaves as the plant grows to give it an arching canopy.

Fertilizer

For the best results, you want to give your dumb cane plant an application of fertilizer every four to six weeks. Pick out a 20-20-20 fertilizer, and follow the product label instructions for dosing. Some people choose to use a very diluted liquid fertilizer every time they water.

Light

Dumb cane plants are very popular indoors because they do very well grown in shady conditions, but they appreciate bright light exposure in the winter. During the spring and summer growing seasons, you can put it in indirect lighting or dappled shade. The plant will favor whichever side faces the light, so rotate the plant once in a while to keep the growth balanced.

Lighting plays a critical role in the health of your plant, so make sure you put it in a location that gets plenty of indirect but bright light.

Soil

Use a very well-aerated, fast-draining potting mix for this plant. Making sure the soil has great drainage will help avoid root damage, and you never want to leave it sitting in soggy soil.

Temperature and Humidity

This plant thrives in fairly warm conditions, from 65°F to 75°F. If the temperature around the plant dips below 60°F or you accidentally expose your dumb cane plant to cold drafts, it’s very likely to lose the lower leaves and take on a palm-like look.

Water

During spring and summer, dumb cane plants like regular moisture and they don’t want to ever dry out completely. A large plant may need watering twice a week. During the winter months, you can reduce your watering schedule. You also want to be very careful that you don’t overwater this plant as this can lead to rot. Make sure the top two inches of the soil dries out before you water it again.

Propagating the Dumb Cane Plant

There are several ways you can propagate this plant in your home, including using air layering, division, or stem cuttings. When you cut the foliage, roots, or stems on these plants, make sure you want to start with a sterilized knife or scissors and clean everything after you finish.

Wash your clippers with soap and water or rub them into a cloth that you dipped in a 10:1 mixture of water and bleach to prevent disease spread. Also, make sure you don’t come into contact with the plant’s sap, and make a point to propagate in the early summer or late spring months.

Air Layering

Air layers works to open the stem of your dumb cane plant to encourage new roots to form before you separate the new growth from your current plant. If your plant has a centralized stem that is a minimum of 12 inches tall, you can air layer it to get a new plant. Get some clear plastic gallon bags, twist ties, zip ties, or string and a clean, sharp knife, cotton swabs or small brushes, toothpicks, sphagnum moss, rooting hormone gel or powder, and get ready to start. You’ll also need to have a pair of sterilized scissors or clippers.

If the plant has already dropped the leaves and exposed the stem, pick a spot roughly halfway up the stem to make the first cut. If not, you’ll trim away the leaves from this area using a pair of clippers to give yourself a clear work space. You’ll need roughly three inches of space free of foliage. Leave the plant’s foliage on above and below this space. You don’t have to be 100% exact in your measurements here, but you want to put your cut roughly four inches from the stem’s tip.

Take your clean, sharp knife and make a 45° incision at an upward angle in the stem. You want to cut halfway through where you want the new root system to form. Apply your rooting gel or hormone inside of the cut with a cotton swab or small brush. Once you finish, stick a toothpick horizontally into the cut to ensure that it doesn’t close over and heal before it forms roots. Clip away the excess length.

Dip the sphagnum moss into water and wring it out. Pack the moss around your cut stem so that it’s completely around it. You want to have a minimum of two inches of moss below and above your cut portion. Wrap plastic around the moss to hold it in place and secure it with your twist ties, zip ties, or string at the bottom and top.

Put your plant in indirect, bright light and water it like you normally would. Open the plastic a few times a week to make sure the moss is still damp. If it’s not, pour a small amount of water in or mist it. Roughly six weeks later, you should start seeing roots filling in around the moss. If you don’t yet, don’t make a big deal out of it as the roots can take up to three months to form. When you can see the new roots, it’s time to separate the new plant from the existing one.

Cut the top of your dumb cane plant just below your plastic using a clean knife or scissors. Remove the moss, plastic, and the toothpick and plant it like you would any transplant. You can get rid of the original plant, or you can put it in indirect sunlight and keep watering it so it forms a new shoot from the base. Trim the plant’s stem back to roughly an inch above the soil to encourage bushy, new growth. Water it when the top inch of soil is dry to the touch.

You want to take care to ensure that you get a very sharp pair of scissors or a knife to make clean cuts on your plant when you propagate it.

Division

If your dumb cane plant has one stem, you can’t use division. This method for propagating it will only work if you have a plant with several stems in a single root ball. Dividing your plant is a nice way to get a new dumb cane plant, and it’s also a good idea to consider doing so if your current plant is getting too large for your space or outgrowing the current container.

To use division, gently remove your plant from the container by tipping the container sideways and running a clean knife around the pot’s perimeter. Grasp your dumb cane plant by the base of the stems and remove it from the pot. Now, look and find a spot to split your plant. You want to find a space where the plant naturally divides and has roots intact among the stems. Avoid splitting any stems that are very close together.

Clean away as much of the soil as you can to expose the root system and gently tug the sections apart as much as you can. If the roots refuse to come cleanly come apart, get a clean knife or a smaller saw  and cut the roots apart. Trim away any roots that feel mushy or soft or brittle and dry. Put half of the plant into the original container with fresh soil, making sure that it’s in the same depth as before. Plant the second section in a new pot with clean soil and water it in.

Stem Cuttings

Finally, it’s possible to propagate your dumb cane plant using stem cuttings. This is the easiest method to use if your plant already dropped the lower leaves to expose the stem, but you can easily trim away existing leaves to get to the stem. Each section that you cut has to have at least one node or band, and this is the point where the leaves attach to the stem.

The goal is to make a few cuttings that are two or three inches long. Depending on the stem’s length, you may be able to take multiple pieces to transplant. Use a clean, sharp pair of clippers or a knife to cut sections from the stem. Make sure that there are a few leaves attached to the top section. Remember that the cuttings don’t need leaves to root, but this can speed things up a little. Dip the bottom of each cutting into rooting gel or hormone.

Put the stem in potting soil, making sure it’s upright. Bury it until it’s roughly half below the soil. To make things easier, you may want to root your cuttings into the pot that you’ll keep the mature plant in, but you can also put them in a temporary container. Water your cuttings and ensure that the soil doesn’t dry out as they sprout.

Place your new plants in a space where they can get indirect sunlight. You can keep the original stump of the plant and allow it to send up new sprouts, like you can with air layering. After a month or two, you should start to see new growth from the top of your cuttings, and leaves will follow. Cuttings you took from lower down on the stem will take longer to root than cuttings from the higher portions of the stem. When they have two or three leaves on them, it’s time to transplant.

Transplanting and Repotting the Dumb Cane Plant

If you get a store-bought dumb cane plant, you’ll want to repot it. Pick out a new container that is at least as big as the plant’s current container or you can go a few sizes larger. The container should have one drainage hole at a minimum to allow the excess water to run out.

Get a well-drained, loamy potting soil that has coconut coir or peat moss for your new plant. You want to get a soil that drains well but will retain some water. Some will also come with fertilizer built in, so you won’t have to feed your plant again until six months or so after you plant it.

Put some soil in the bottom of your new container to ensure that your plant is at the same depth as it is in the current container. Make sure the soil is slightly moist in the original container before you start this process. Remove the plant from the current pot by gently loosening it up. Carefully tug the plant to remove it by gripping it at the base.

Put your plant in the container and fill around it with your chosen soil. Pack the soil down and give it a watering in, allowing the excess to drain out of the holes in the bottom of your container. Repot it every year or two years to keep your dumb cane plant happy. If you see the root start to poke up through the soil or ring the container’s perimeter, it’s time to repot it.

Even if you don’t repot it, you’ll want to refresh the soil every two years or so. Old soil loses nutrients and gets compacted. Get a new container that is a few inches larger than the current one and follow the instructions we outlined to repot it.

You will have to refresh the soil every two years or so as the plant will use a lot of nutrients to grow, even if it doesn’t outgrow the current pot.

Pruning and Maintenance with the Dumb Cane Plant

You won’t have to prune the dumb cane plant. However, if you find that some of the leaves are brown, yellow, shriveled, or unattractive, you can trim them away using a clean pair of clippers. If your plant gets leggy and tall and has an exposed stem, you can propagate it using stem cuttings to make it bushier.

If you don’t like how your dumb cane plant looks when it gets leggy and tall but you don’t want to propagate it either, you can get rid of it and start over. You can cut the stem an inch above the soil and put it in a spot that gets bright but indirect light and keep the soil moist. In a few months, you’ll see new growth emerge from the base of the stem. Dust the foliage every few weeks using a damp cloth as leaves that have a layer of dust on them don’t photosynthesize correctly.

Managing Pests and Diseases

This is a very sturdy plant that doesn’t have issues with most diseases or pests. If you keep them healthy by fertilizing, watering well, repotting, and dusting as needed, it’ll have a better chance of withstanding potential issues. There are a few things you should keep an eye out for, including:

Diseases

Even though it’s not common, it’s not 100% impossible for your dumb cane plant to develop a bacterial or fungal infection. The two common ones to watch out for are:

Anthracnose

The Colletotrichum gloeosporioides fungus is the cause of this plant disease. When it attacks your plants, it causes brown or tan circular spots with yellow margins on the foliage. Spots may look dry or wet, and neem oil is a great option to start controlling this disease. Combine one part water with three parts neem oil and spray the foliage once every few days for a few weeks until you start to see new, healthy foliage. The leaves that have holes won’t heal, but they should improve.

Bacterial Leaf Spot

Bacterial leaf spot will cause small gray or green circles to appear on your plant’s leaves. As the disease gets worse, the spots can get larger and merge to form a lesion. The spots can turn black or brown and the centers will eventually fall out. The leaves may also turn a sickly yellow.

Erwinia carotovora or E. chrysanthemi are the causes of this disease, and there is no cure for it. You want to strip off any infected leaves and water at the soil level to prevent the disease from spreading as a preventative measure. You also want to make sure that you sanitize your tools before and after you use them on any sick plants using a 10:1 mixture of water and bleach. If you don’t, you run the risk of spreading the disease to other plants. If all of the stems on your plant get sick, you have to toss it out.

Insects

There are a also a few bugs that can impact you dumb cane plant. While there aren’t a huge amount, the usual pests can lurk in the plant.

Aphids

Aphids are a very common insect pest both outside and inside. There are thousands of different species, and hundreds of them like to feed on ornamental plants and vegetables. The adults are roughly ⅛ of an inch long, and they can be green, tan, pink, yellow, white, gray, or black in color. They suck on the leaves and stems of your plants. As they feed, they’ll release a sticky substance called honeydew. This sticky yellow substance can attract sooty mold and ants.

Plants that have severe infestations going on can have yellowing leaves, yellow spots, or stunted growth. The first thing you want to do is take your dumb cane plant to the sink and spray the leaves using a strong blast of water. This will dislodge a lot of aphids and you can wash them down the drain. Dilute neem oil and spray your plant’s foliage, making sure that you get the underside of the leaves where the aphids like to hide. Reapply the neem oil after a week.

Aphids can wreak havoc on your dumb cane plant if you don’t take steps to remove them when you first notice them.

Mealybugs

If you’re looking at your dumb cane plant one day and you notice that it has little fluffy cotton bits on it, you’ve most likely got a mealybug infestation going on. These small pests come from the Pseudococcidae family, and their soft bodies are covered in a waxy, fluffy, white material. They like to hang out on the underside of the leaves and on the plant’s canes, and they suck the sap out of the plant. In turn, you’ll see yellow leaves and stunted growth. A severe infestation can kill the plant. If this all isn’t bad enough, these pests also secrete honeydew that can attract sooty mold.

To take care of them, if you don’t see a large number of pests on your plant, dip a cotton swab in rubbing alcohol and wipe the bugs one at a time. Don’t get alcohol on your plant because they can cause foliage damage. If you have a bigger infestation, get insecticidal soap and douse your plant.

Bottom Line

Dumb cane plants have a lot of offer without needing a great deal of care in return. Give them a space, feed them every few weeks, water them, and they’ll bring both texture and color to the room. The patterns on the leaves make them very pretty, so they make great statement pieces.