Dumb cane (Dieffenbachia seguine) care

Aroids · easy to keep

Dumb cane: big paddle leaves splashed with cream, on a thick upright cane that goes bare at the bottom as it ages. It grows fast and takes low light, and the common name is a genuine warning — chewing a leaf swells the mouth and tongue enough to stop you speaking, which is worth knowing if there are small children about.

Quick facts

Water

Water weekly. Water when the top half of the pot is dry. Aglaonemas tolerate a missed week far better than an extra one.

Light

Bright indirect light.

Humidity

Room humidity is fine.

Soil

Standard compost with perlite.

Feeding

Balanced feed at half strength monthly in spring and summer.

Repotting

Repot once a year.

Toxic to pets

Toxic to cats, dogs and people. The common name — dumb cane — comes from the effect of chewing it: the calcium oxalate crystals swell the mouth and tongue and can make speech and swallowing painful for days. Worth placing out of reach of small children.

Difficulty

Easy.

Mature size

1–1.5 m tall.

Native to

The Caribbean and northern South America.

Watering a Dumb cane

Water weekly. Water when the top half of the pot is dry. Aglaonemas tolerate a missed week far better than an extra one.

That cadence is the one PlantParlour sets for this species when you name it, and it is deliberately on the cautious side — a plant that asks a day early is safer than one that asks a day late. Log each watering and the reminder moves with the plant rather than with the calendar.

Light

Medium indirect light suits the green and silver varieties, which is why they end up in offices. The pink, red and cream cultivars carry far less chlorophyll and need genuinely bright indirect light to keep their colour and keep growing.

Humidity and temperature

Room humidity is fine. Central heating in winter is what turns a comfortable room into a dry one, and it is the usual reason an established plant suddenly browns at the edges or picks up spider mites.

Soil and potting

Ordinary potting compost with a third perlite. Aglaonemas are not fussy; they only object to sitting wet.

Feeding

Balanced feed at half strength monthly in spring and summer. Stop feeding in autumn and start again when you see new growth in spring — feeding a plant that isn't growing just builds up salts in the pot.

Repotting

Repot once a year. Every second or third spring. They are slow and are perfectly happy slightly potbound.

Common problems

• Leaning hard toward the window

  Uneven light. Dieffenbachia grows toward it faster than most.

  Fix: Turn the pot a quarter turn every week.

• Bare stem with a tuft of leaves on top

  Normal ageing.

  Fix: Cut the crown off with 10 cm of stem and re-root it; the stump usually shoots again.

• Yellow lower leaves

  Overwatering, or cold water.

  Fix: Let it dry down further and use tepid water.

Propagation

Divide the clump, or root a stem cutting with two or three nodes in water.

A cutting taken in PlantParlour keeps its link to the plant it came from, so a propagation years later still traces back to the mother plant — which is the point if you ever sell or trade it.

Toxicity and safety

Toxic to cats, dogs and people. The common name — dumb cane — comes from the effect of chewing it: the calcium oxalate crystals swell the mouth and tongue and can make speech and swallowing painful for days. Worth placing out of reach of small children.

Named cultivars and variegations

Dieffenbachia seguine is sold under several cultivar names. Care is the same unless noted; variegated forms carry less chlorophyll, so they grow more slowly and want more light than the plain species.

Questions people ask

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