Dumb cane
Dieffenbachia seguine · also called Dieffenbachia
Foliage and indoor
- Light
- Part sun
- Pot size
- Large pot (more than 15 litres)
- Care level
- Moderate
- Year round or seasonal
- Kept year to year; in a pot, keep it above about 12.8 °C (55 °F)
- Pets
- ASPCA: toxic to pets
Light and position
Indirect light or part shade; protect it from direct sun and cold draughts.
Size and pot
NC State lists 3 to 8 feet tall. Our pot band: large pot (more than 15 litres).
Watering
Water thoroughly, then let the top inch (about 2.5 cm) of soil dry completely before watering again.
Potting mix and feeding
Loose, fertile soil rich in organic matter.
Growing through the year
Prefers moderate temperatures and high humidity.
Winter outdoors
Cold limit in a pot: about 12.8 °C (55 °F). NC State gives no temperature for this plant and lists it only for USDA zones 10a to 11b, the tropical end of the scale. For tropical plants like this we follow NC State’s container chapter: bring tender plants inside once nights drop to 55 °F. NC State also says to protect it from cold draughts.
| Your coldest winter nights | What to do |
|---|---|
| Coldest nights 15 °C or warmer | Can stay out through this winter |
| Coldest nights 10 to 15 °C | Move it to shelter before nights fall to 12.8 °C |
| Coldest nights 5 to 10 °C | Move it to shelter before nights fall to 12.8 °C |
| Coldest nights 0 to 5 °C | Move it to shelter before nights fall to 12.8 °C |
| Light frost: nights down to about −5 °C | Move it to shelter before nights fall to 12.8 °C |
| Hard frost: nights below −5 °C | Move it to shelter before nights fall to 12.8 °C |
A plant can stay out only when its limit is below the coldest night in your band; a limit equal to that night counts as needing shelter. A rare cold snap, wind or a wet pot can still damage plants. We convert °F to °C with NIST’s formula.
Watch for
Scale, aphids, fungus gnats, whiteflies and spider mites; leaf spot and root rot. The sap irritates skin, so wear gloves when cutting.
Pets and people
ASPCA lists dieffenbachia as toxic to dogs and cats (insoluble calcium oxalates and a proteolytic enzyme). NC State rates its toxicity high and warns it may be fatal to pets and livestock.
General gardening information, not professional advice. Plant toxicity details are a starting point, not veterinary or medical advice: if a pet or child may have eaten a plant, contact a veterinarian or doctor promptly.
Care level: NC State’s maintenance rating (Medium). Pot band and summary wording are ours, based on the sources below.