Dieffenbachia (Dumb Cane) Plant Profile

dumb cane plant

The Spruce / Krystal Slagle

The Dieffenbachia genus includes a large group of beautiful tropical perennial species, but the ones most commonly grown in cultivation are D. sequine, D. oerstedii, D. maculata, and D. amoena. Several Dieffenbachia species have recently been reassigned with different names, so you may run into confusion on the precise naming of different varieties. Collectively, they are generally known as dieffenbachias or dumb canes.

Dieffenbachias​ feature pointed, ovate leaves in a variety of combinations of green, cream, and white colors. A large, well-grown dieffenbachia can reach 10 feet, with leaves 20 inches long. However, the plants will rarely reach this size in typical indoor conditions.

closeup of dumb cane leaves
The Spruce / Krystal Slagle
closeup shot of a dumb cane plant
The Spruce / Krystal Slagle
Botanical Name Dieffenbachia spp.
Common Names Dieffenbachia, dumb cane, mother-in-law's tongue
Plant Type Herbaceous perennial (usually grown as a houseplant)
Mature Size 3 to 10 feet tall
Sun Exposure Part shade to full shade
Soil Type Peaty, well-drained potting soil
Soil pH 6.1 to 6.5
Bloom Time Seasonal bloomer
Flower Color White
Hardiness Zones 10 to 12 (USDA)
Native Area Caribbean, South America

How to Grow Dieffenbachia

Dieffenbachia is best grown as an indoor plant in bright, indirect sunlight. Plant it in fertlile, well-drained potting soil with a high peat content. It will do best in high humidity. One way to provide this is to place the pot on a tray of pebbles that is kept wet.

Light

Dieffenbachia plants appreciate bright light during the winter months. During the growing season, the plant prefers dappled shade or indirect light.

Soil

Use a fast-draining, well-aerated potting mix. Make sure their drainage is good to avoid damaging the roots; they should never be left in soggy soil.

Water

During the growing season, Dieffenbachias like regular moisture and do not want to dry out. A large dieffenbachia might need to be watered twice a week. In the winter, cut back on the water.

Temperature and Humidity

This plant likes above-average warmth. If the temperature drops below 60 degrees Fahrenheit or if the plant is exposed to cold drafts, it is likely to lose lower leaves and assume a palm-like appearance.

Fertilizer

For best results, feed regularly (every 4 to 6 weeks) with a balanced, diluted fertilizer, such as a 20-20-20.

Potting and Repotting

Repot annually for best results—simply lift the plant as a whole, knock away any old soil and dead material from the roots, and replace it in a larger container. Watch out for signs of stress on the plant, like roots poking out from the surface, crowding, or falling leaves, which could signal that the plant needs repotting. After repotting a dieffenbachia, give it some time to adjust to its new setting. Make sure to wear thick gloves, or else you risk hurting yourself by contact with the milky, mildly toxic sap.

Propagating

There are several possibilities for propagating a dieffenbachia:

  • During repotting in the spring, offsets can be divided (leaving some roots intact) and planted in their pots. If you take this route, make sure not to damage the root systems of the parent plant in the process, and use a sterilized tool to avoid spreading disease.
  • In older, leggy dieffenbachias, the top can be cut off and potted into fresh potting soil with a rooting hormone. New leaves will sprout from the stump.
  • Pieces of the cane can be sprouted by laying them horizontally in damp potting soil.

Varieties of Dieffenbachia

Of the many species of Dieffenbachia, only a few are commonly sold commercially

  • D. seguine is the most popular Dieffenbachia species, a native of Brazil with clusters of large ovate leaves with green margins splotched with yellow or cream color. It can grow as tall as 10 feet.
  • D. maculata (formerly known as D. picta). Good cultivars include 'Perfection', with intensely variegated 8-inch leaves; 'Rudolph Roehrs', with fully yellow leaves with ivory splotches; and 'Superba', with thicker leaves and white variegation.
  • D. amoena is a large, 6-foot plant with 20-inch leaves. One notable cultivar is 'Tropic Snow', which has smaller leaves and more variegation.

Be aware that various species of Dieffenbachia have undergone reassignment, and species names may change.

Toxicity of Dieffenbachia

Dieffenbachia contains oxalic acid and calcium oxalate crystals that can cause burning and swelling of the lips, tongue, and throat. It can cause difficulty speaking and swallowing (hence the "dumb cane" common name), and nausea, vomiting, and diarrhea. The poisoning is rarely fatal to humans, but you should contact your local poison control agency if any portions of the plant are chewed or ingested. Dieffenbachia is sometimes fatal to pets and livestock.

Remember to wear gloves when exposure to the sap is possible. This plant is best for experienced gardeners who have the skills to keep it alive and help it flourish

Common Pests/Diseases

Watch out for common houseplant pests—like scale and spider mites—which cause exterior damage. In small-scale cases, they can be simply wiped away manually, but a more significant infestation could require the use of a good, strong pesticide.