When to Plant Alocasia (Repot and Propagate)

Alocasia has two calendars. Gardeners in frost areas grow it as a summer plant that goes out after the last frost and comes back in or gets lifted in fall. Indoors, the timing that matters is when to repot and divide.

Planting outdoors in frost areas

NC State recommends starting corms in pots indoors and setting them outside after your last frost date. Frost-free isn’t quite enough on its own, though. Wisconsin Extension notes that elephant ears falter when temperatures stay below 50°F for long, and they sit idle in cool spring weather until real summer warmth arrives. Colorado State’s rule for moving any houseplant outdoors fits well: wait until frost danger has passed and nights stay above 50°F.

For a head start, pot up the corms indoors in March with the top of the corm close to the soil surface and keep them somewhere warm. Wisconsin Extension says the first leaves take a few weeks to appear and that Midwest gardeners usually plant out in late May or early June.

Toughen up indoor-grown plants before they go out. Colorado State advises a few days in shade before gradually giving them more light, and shelter from wind. Alocasia leaves tear easily, so choose a protected spot. Give it partial or dappled shade, and if it goes in the ground, plant it in rich, moist, well-drained soil. UF/IFAS spaces garden plants 36 to 60 inches apart.

Planting in warm-winter areas

UF/IFAS lists alocasia planting as year-round in zones 8 through 11 in Florida; freezes kill the leaves, but plants in zone 8A and warmer regrow from the base. NC State rates it hardy only in zones 10-12, so in zones 8 and 9 expect winter dieback and treat a mild winter as a bonus.

Bringing it back in or lifting tubers

You have two choices in fall in frost areas.

Bring the pot indoors. Iowa State advises bringing houseplants in once nights consistently dip to around 50°F, and Wisconsin Extension says to bring elephant ears you plan to keep as houseplants indoors before temperatures reach the 30s °F. Before the plant comes inside, check it over for pests. Alocasia is prone to spider mites, and mealybugs and aphids also show up. Rinse the foliage outdoors, let it dry, and keep the plant away from your other houseplants for 3 to 4 weeks, which is about how long Iowa State says it takes hitchhiking pests to show themselves. Wisconsin suggests cutting it back to its top two leaves, giving it bright light at room temperature and keeping the mix on the dry side until spring.

Lift and store the tubers. Purdue says elephant ears should be dug just before or soon after a light frost. Cut the stems back to 3 to 6 inches, then leave the tubers somewhere warm for 7 to 10 days to dry the surface. Pack them between layers of dry vermiculite, peat moss or sawdust in a sturdy box and store at 50 to 60°F. Replant after the last frost the next year. This only works for plants that have formed corms. Wisconsin Extension says plants without them are harder to carry through winter, though they may survive as houseplants in a warm, bright spot.

When to repot

Spring is the best time to repot houseplants, says N.C. Cooperative Extension, because the plant has a whole growing season to fill the new pot. For alocasia, that means repotting as new leaves start in spring, which is also when Wisconsin Extension says to resume regular watering and feeding. Alocasia grows fast, so check every spring.

Signs it is time:

• Roots growing out of the drainage holes or along the soil surface
• The pot drying out much faster than it used to
• Lower leaves yellowing, or growth stalling even though you feed it

Go up no more than 2 inches in pot diameter, use a rich potting mix that holds moisture but drains well, and choose a pot with drainage holes. Don’t add a gravel layer at the bottom, since it slows drainage rather than helping.

When to divide

Alocasia is propagated by dividing off offsets, the small side corms that form beside the main one. The easiest times to do it are when you repot in spring or when tubers are out of the ground for storage. Pot each piece in fresh mix and keep it warm and evenly moist until new leaves appear. Wear gloves, because the sap contains calcium oxalate crystals that irritate skin.