Dieffenbachia (Dumb Cane): Care, Pruning and Toxicity

Dieffenbachia is a fast-growing plant with large variegated leaves that becomes a real indoor tree within a few years. It is undemanding, happy in indirect light and easy to propagate. It is also one of the most poisonous houseplants, so it pays to know the safety rules in advance. Here is how to care for, rejuvenate and propagate it without risk to yourself, children or pets.

What is dieffenbachia and its varieties

Dieffenbachia is an evergreen plant of the arum family from the tropics of Central and South America. It has a thick, succulent stem and large oval leaves splashed with white, cream or yellow. The most common indoors is D. seguine (formerly D. maculata), with varieties such as Camille (almost cream leaves with a green edge), Tropic Snow, Compacta, Reflector and Mars. D. amoena is larger, up to 1.5–2 m, with long leaves and striped markings.

Light and temperature

It needs bright indirect light: variegated types turn green in shade and the stem stretches. Midday sun scorches the leaves. Dieffenbachia leans towards the window, so turn the pot weekly for even growth. Keep it at 20–25 °C, not below 16–17 °C in winter, away from draughts and cold sills.

View full-size photoDieffenbachia thrives in bright indirect light.

Watering, humidity and feeding

Water generously in summer as soon as the top 2–3 cm dry; more sparingly in winter. Standing water rots the stem base. It likes humid air: mist regularly and wipe the leaves with a damp sponge (wearing gloves). Feed every 2 weeks from spring to autumn.

Why the stem goes bare and how to rejuvenate it

As dieffenbachia ages its lower leaves naturally die, leaving a bare “trunk” with a tuft on top; low light, cold or overwatering speed this up. To restore a full plant, in spring cut off the top with 10–15 cm of stem and root it. Keep the 10–15 cm stump: side buds will sprout and make it bushier.

Propagation from tops and stem pieces

• Tip cuttings — let the cut dry for 1–2 hours, then root in water or damp sand and peat; roots appear in 2–4 weeks.
• Stem sections — cut a bare stem into 5–10 cm pieces with 1–2 dormant buds, lay them on moist mix, press in lightly and cover; new plants grow from the buds.
• Air layering — for tall plants: make a shallow cut in the stem, wrap with damp sphagnum and film, and sever the top once roots form.

Always wear gloves. For soil and repotting, see how to repot houseplants.

View full-size photoPropagate dieffenbachia wearing gloves for safety.

Common problems

• Yellow lower leaves — natural ageing, cold or overwatering.
• Brown edges — dry air or hard water.
• Fading variegation — too little light.
• Soft stem at soil level — rot from overwatering; root a healthy top immediately.
• Spider mites, scale — the most common pests.

More in houseplant problems and symptoms.

Is dieffenbachia poisonous: safety rules

Yes, and it is the plant’s main drawback. The name “dumb cane” comes from the fact that its sap, if chewed, causes intense burning and swelling of the tongue and throat, making it hard to speak. The cause is needle-like calcium oxalate crystals and irritants in the sap, which also irritate skin and eyes.

• Prune and repot only in gloves; wash hands and tools afterwards.
• Keep it out of children’s rooms and away from cats and dogs.
• If sap gets in the mouth or eyes, rinse with water and see a doctor or vet.

Safer alternatives: calathea and the spider plant. More in houseplant names and care; browse potted plants.

FAQ

Is dieffenbachia safe with children at home?

Better not, or only well out of reach. The sap causes severe irritation of the mouth and throat.

What do I do with a bare dieffenbachia stem?

Cut and root the top, and cut the stem into sections to propagate. The stump left in the pot will sprout new shoots.

View full-size photoDieffenbachia sap is toxic—keep the plant away from children and pets.

Does dieffenbachia flower?

Mature plants sometimes produce a greenish spathe. Flowering weakens the plant, so the stalk is often removed.

Author: Maria Svitlovir

Graduated from Taras Shevchenko National University of Kyiv, Institute of Biology and Medicine (2001). BSc in Biology, MSc in Horticulture. Writes about plants, works at a garden centre selecting and repotting plants, and contributes to plant reference guides.

About the author →