Dumb Cane Guide: How to Grow and Care for Dumb Cane

Dumb Cane, or dieffenbachia, is a tropical perennial plant that is native to South America and the Caribbean. This plant grows large, oval green leaves from large, green stems. In the right conditions, dumb cane will produce green flowers that look like peace lilies, but this rarely happens when it grows indoors.

Dumb canes are popular indoor plants that require little maintenance. Most species can survive in any light conditions except for full sun. Even if it is a popular house plant, dumb cane is considered toxic because it causes the mouth to swell when it is ingested.

There are a number of species of dumb cane, but the most popular and commercially available varieties have been specially cultivated for indoor growth. Here are three common cultivars of dieffenbachia.

1. 1. Dieffenbachia seguine: D. seguine is one of the most popular dumb cane species and is native to Brazil. These plants can grow up to 10 feet high and their leaves can grow up to a foot long.
2. 2. Dieffenbachia maculata: D. maculata is a far more compact plant than d. sanguine that only grows about three feet in height. This species is also known as “tropical tiki” and features variegated leaves that are green with streaks of white.
3. 3. Dieffenbachia amoena: D. amoena, or “charming dieffenbachia”, is a large species of dumb cane that can grow to about six feet high with 20-inch long leaves. D. amoena “Tropic Snow” grows slightly smaller dark green leaves.

All varieties of dieffenbachia are perennial plants which means that they can be grown year-round indoors. They should only be planted outside if you live in a tropical climate, or in high, humid temperatures found in USDA hardiness zones 10–12. If the temperatures in your area dip below 60 degrees Fahrenheit in the winter, you should grow dumb cane inside. Spring is the best time to propagate dumb cane, right before the growing season begins. As long as they are cared for properly, dumb cane can live for several years.

Dumb cane grows quickly when it receives proper care. A rooted cutting may even reach two feet in height after its first year of growth. The best way to grow the plant is to propagate it from cuttings, and here is how to do that.

1. 1. Prepare and clean your equipment. Sterilize your pruning shears with a combination of oil cleaner and water before you get started. This will protect your plant from bacteria and contaminants. Also be prepared with gloves, a facemask, and protective clothing to limit your contact with the toxic sap of the plant.
2. 2. Make your stem cuttings. Pick a stem of an existing plant that you would like to use to propagate a new plant. Stem tips taken from the top of the plant typically root the fastest, but you also may take cuttings from the middle or base of the plant. Cut as many four to six-inch-long pieces of stem as you intend to plant to increase the likelihood that your plant will root.
3. 3. Prepare your cuttings. Carefully remove the leaves from your stems and place them in jars of water. Keep these jars in warm, well-lit spots in your home, but keep out of direct sunlight. Change the water out every few days. Keep these cuttings submerged for a few weeks, or when you begin to see new roots forming.
4. 4. Choose the right location and container. Dumb cane is a low-light plant that does not do well in direct sunlight or even bright light. Indirect light or partial shade is ideal, but your plant should be just fine in full shade. Choose a container for your plant that is large enough to accommodate a large root ball, so that your plant’s roots don’t get too crowded.
5. 5. Transplant your cuttings. When roots begin to grow, remove your cuttings and place each one into a small container filled with well-draining potting soil. Use a potting mix that is two parts peat moss and one part perlite. Water the newly transplanted or repotted plants twice a week for the first few weeks to help them get established.

While dieffenbachia care may be simple, the right kind of support can keep your plant thriving for years with minimal effort. Here are a few tips on how to care for your dumb cane plant.

1. 1. Water occasionally. Dumb cane can tolerate the occasional missed watering, as long as you keep the top two inches of soil moist. Overwatering is often the most common problem you will have with dumb cane, and can lead to yellowing leaves and root rot.
2. 2. Feed your plant. Fertilize your dumb cane plant every two to four weeks during the growing season. Dilute any houseplant food with an equal amount of water, then spread over your soil.
3. 3. Monitor your plant for pests. Dust or wipe your plant with a damp cloth every few weeks to safeguard against scale and aphids. If you begin to notice spider mites or mealybugs, dip a cotton ball in rubbing alcohol and wipe it on the area.

Dumb cane is toxic to both humans and animals. The leaves and stems are covered in calcium oxalate crystals. When chewed or swallowed, these crystals—along with the oxalate acid inside the plant—can potentially cause enough swelling of the tongue and throat to inhibit breathing and swallowing.

The name “dumb cane” comes from the temporary speechlessness and tongue-swelling that occurs after chewing its stem. Dumb cane sap is also an irritant that can make the skin numb. Households with many children or curious pets should avoid keeping dumb cane as a house plant.

Grow your own garden with Ron Finley, the self-described "Gangster Gardener." Get the MasterClass Annual Membership and learn how to cultivate fresh herbs and vegetables, keep your house plants alive, and use compost to make your community—and the world—a better place.