How to Grow and Care for Dieffenbachia (Dumb Cane)

Dieffenbachia is a genus of tropical perennials with several species that are commonly grown as houseplants. They 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, where 3 to 5 feet is more common.

Dieffenbachia is a fast-growing plant that can achieve 2 feet in height within a year of planting a rooted cutting, provided it gets enough light. Though the name "dumb cane" has fallen out of favor as a derogatory term, it got that name because the plant contains toxins in all of its parts (including its roots and sap) that, if it is in contact near the face or ingested, it can inhibit speech. It is highly toxic to humans, dogs, and cats.

Dieffenbachia Care

Dieffenbachia is best grown as an indoor plant in bright, indirect sunlight. Plant it in fertile, well-drained potting soil with a high peat content. As a tropical plant, it will do best in high humidity. One way to provide this is to place the pot on a tray of pebbles filled with water. Misting the leaves can help during the dry winter months.

Like many indoor houseplants, overwatering is a common problem with this plant. Allow the top 2 inches of potting soil to dry out completely before watering thoroughly so that moisture drains through the bottom of the pot. If you wish, lower, weak leaves can be removed as the plant grows, creating a specimen resembling a small palm with an arching canopy.

Planting

If you live in a warm climate, plant dieffenbachia outdoors in your shade garden where it can enjoy a little dappled light. Plant outdoors in the early spring and water twice a week until the end of summer and early fall. If you are planting more than one dieffenbachia in a garden, give them plenty of space (a few feet between each) as the plant can grow tall and a few feet wide. When planting indoors, consider placing the dieffenbachia plant in a naturally humid area, like a bathroom or kitchen, where it will thrive. If you place the plant in a dry area of your home, consider misting it or putting it on a rock tray filled with water that will naturally evaporate and create humidity around the plant.

Light

Dieffenbachia plants are popular indoor plants largely because they do well in shady conditions, but these plants do appreciate bright light during the winter months. During the growing season, the plant prefers dappled shade or indirect light. The plant will favor the side facing the light, so periodically rotate the plant to keep its growth balanced.

Soil

Use a fast-draining, well-aerated potting mix. Make sure 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, you can cut back on the water. At the same time, it's important not to overwater a dieffenbachia, which can cause rot problems. Make sure the top of the soil is fully dried out before watering.

Temperature and Humidity

This plant likes fairly warm conditions, from 65 degrees to 75 degrees Fahrenheit. If the temperature drops below 60 degrees or if the plant is exposed to cold drafts, it is likely to lose lower leaves and assume a palm-like appearance. The plant appreciates high humidity.

Fertilizer

For best results, feed regularly (every four to six weeks) with a balanced, diluted fertilizer, such as a 20-20-20. For the amount to use, follow product label instructions. However, some growers swear by a routine of using a weak diluted fertilizer at every watering.

Types of Dieffenbachia

The Dieffenbachia genus includes a large group of beautiful tropical perennials, 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 about the precise naming of different varieties. Collectively, they are generally known as dieffenbachias or dumb canes.

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

• D. seguine, the most popular Dieffenbachia species, is 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), offers good cultivars that 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. 'Camille' has pale yellow leaves with white margins and grows to about 3 feet.
• 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.

Pruning

A dieffenbachia plant usually requires pruning when it's too tall and there seem to be few leaves on the lower part of the stem. With a sterilized, sharp cutting tool, prune the plant down to size from the top to trigger new growth.

Propagating Dieffenbachia

Though you can grow dieffenbachia from seed, it is challenging, requires pollination, and is best left to commercial propagators. There are three better and easier ways to propagate a dieffenbachia plant.

To divide by root division:

1. During repotting in the spring, divide offsets, leaving some roots intact.
2. 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.
3. Plant each offset in a pot filled with fast-draining potting mix and water well.

To propagate a stump:

1. In older, leggy dieffenbachias, cut off the top of the plant.
2. Dip the cut end in a rooting hormone.
3. Plant in a pot with fast-draining potting mix. New leaves will sprout from the stump.
4. Once new leaves appear, remove the older leaves.

To propagate with cane cuttings:

1. Pieces of the cane can be sprouted by laying them horizontally in damp potting soil.
2. As the pieces take root, leaves will gradually sprout.
3. Plant each rooted piece in its own pot filled with fresh potting mix.

Potting and Repotting Dieffenbachia

Dieffenbachias often need annual replanting. Watch out for signs of stress on the plant, such as roots poking out from the soil surface, crowding, or falling leaves, which could signal that the plant needs repotting. To repot, simply lift the plant as a whole, knock away any old soil and dead material from the roots, and place it in a larger container with some added fresh soil. After repotting a dieffenbachia, give it some time to adjust to its new setting. Wear gloves to avoid contact with the sap.

Overwintering

Bring a potted dieffenbachia plant indoors during cooler months and keep it in a bright spot where the temperature will stay above 60 degrees Fahrenheit. Water the plant once a week as it won't need as much water as in the summertime.

Common Pests

Dieffenbachia plants are largely trouble-free, but like many indoor plants, they can be susceptible to spider mites, especially indoor plants that are placed in dry air. These pests can be treated with a horticultural oil along with added humidity.

How to Get Dieffenbachia to Bloom

If you like challenges, you will enjoy trying to get a dieffenbachia plant to bloom. As an indoor plant, it can be quite stubborn about blooming, much like the peace lily. To see an unscented flower, which looks like a small white spike, you may have to put the plant outdoors in the warmer months when it may be willing to push out a flower. Put the plant in a bright spot, but not one where it will come in contact with direct sunlight. Be sure to fertilize the plant appropriately for a bloom, as well. As an outdoor plant in zones 11 and 12, however, you may see sporadic blooms if the plant is grown in partial shade and fertilized.

Common Problems With Dieffenbachia

You will be able to tell a lot about your dieffenbachia by the state of its leaves. Watch for certain colorations on the leaves to let you know what to do to amend conditions.

Leaves Turning Yellow

Overwatering or underwatering your plant can turn the leaves yellow. Often, they will also fall off the plant. Check the soil by sticking a finger into the soil up to the first knuckle. If it's wet, hold off on watering for a week or so. You may have to go a little deeper to see if the soil is too dry, which means you need to add water to the plant. Cut off the yellow leaves regardless of the reason.

Leaves could also turn yellow because the plant is lacking nutrients, such as nitrogen. Though this can be tough to diagnose, it won't hurt to use a plant fertilizer to see if will bring your plant back to health.

Drooping Leaves

Dieffenbachia prefers partial shade. If your plant droops, it may mean it's getting too much sunlight. Move the plant to a spot with indirect sunlight. However, if it's not getting enough light, the leaves may turn yellow and droop. Move it to an area with a bit more light to alleviate this problem.

The plant may droop because it is cold or near a draft. Keep your plant in a consistently warm area that's between 65 degrees to 75 degrees.