Alocasia macrorrhizos care guide
Alocasia macrorrhizos, the giant taro, needs bright indirect light, at least 16 °C (61 °F), humid air and plenty of room.
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- Light
- Bright, indirect, no harsh sun
- Water
- When the top 5 cm (2 in) of compost is dry
- Climate
- At least 16 °C (61 °F), above 15 °C (59 °F) in winter
- Humidity
- Humid air, a pebble tray helps
- Pet safety
- Toxic to cats and dogs
Room to grow
Alocasia macrorrhizos is one of the largest alocasias. The RHS gives it an eventual height and spread of 1.5 to 2.5 meters, with very large leaves on thick stalks. Give it a spot where the leaves can spread without brushing walls or people.
Grow it in a heavy terracotta pot, which keeps a large plant from tipping over. Repot it in spring every couple of years, into a pot about 5 cm (2 in) wider, using peat-free houseplant compost mixed with grit, about 3 parts compost to 1 part grit.
In winter it rests and often drops its oldest leaves. Keep it above 15 °C (59 °F), water much less and do not feed it until it grows again in spring.
When and how much water
5 cm (2 in)
When the top 5 cm (2 in) of compost is dry
From April to October, water it when the top 5 cm (2 in) of compost is dry. Water until it runs out of the bottom of the pot, then empty the saucer. Turn the pot a little each time so the leaves do not lean toward the light.
In winter, water only enough to keep the compost from drying out completely. A cool, wet pot is the most common way to lose an alocasia, because the rhizome and roots rot.
Light and placement
Give it the brightest spot you have with indirect light, close to a large window but out of harsh direct sun, which scorches the leaves. In low light it grows slowly and the stems stretch.
Feeding
From April to October, give a general liquid houseplant fertilizer every 2 to 3 weeks. Stop feeding in winter, while it rests.
Temperature & humidity
Keep it at 16 °C (61 °F) or warmer while it grows, away from cold drafts. In winter it can stand a little cooler, but keep it above 15 °C (59 °F). Below 10 °C (50 °F) the leaves are damaged.
Alocasias like humid air from spring to autumn. Stand the pot on a tray of gravel with water just below the surface of the stones, group it with other plants, or use a humidifier. A bathroom with a bright window also works. Dry air browns the leaf edges and brings spider mites.
Toxic to pets?
Yes. Keep it out of reach.
Pet-safety information in the JungleBook uses ASPCA reference data where available. It is reference information, not veterinary advice. ASPCA lists the whole Alocasia genus, so this applies to every Alocasia species, including this one.
Full Alocasia macrorrhizos toxicity guide →
Pet-safe alternatives with similar light
Common questions
How often should I water Alocasia macrorrhizos?
From April to October, water when the top 5 cm (2 in) of compost is dry, until water runs out of the pot. In winter, water only enough to keep the compost from drying out completely.
How big does Alocasia macrorrhizos get?
The RHS gives it an eventual height and spread of 1.5 to 2.5 meters. Indoors it grows more slowly, but plan for a large plant.
Why is my Alocasia macrorrhizos dropping leaves?
In winter it rests and often loses its oldest leaves, which is normal. At other times check for cold drafts, a temperature below 15 °C (59 °F), soggy compost or spider mites.
Why are the leaf edges turning brown?
Dry air is the most common cause. Raise the humidity with a pebble tray, a humidifier or by grouping plants, and keep it away from radiators.
What pests attack Alocasia macrorrhizos?
Spider mites are the most common, especially in dry air. Mealybugs can also appear. Check the leaf undersides when you water.
Is Alocasia macrorrhizos poisonous to cats and dogs?
Yes. ASPCA lists the whole Alocasia genus as toxic to cats and dogs. Chewing it causes mouth pain and swelling, heavy drooling, vomiting and difficulty swallowing. Keep it out of reach and call your vet if your pet chewed it.
Sources
- This guide follows established plant-care guidance and official ASPCA pet-safety references. How we verify our plant data →
- Sources: the RHS Alocasia macrorrhizos profile and the RHS Alocasia growing guide support the light, watering, feeding, temperature, humidity, winter rest, repotting and pest guidance. The NC State Extension record for the related hybrid Alocasia × mortfontanensis supports the pests and the risk of rot from overwatering. The ASPCA Alocasia record supports the pet-toxicity wording.
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