The Alocasia family. The main distinctions between Alocasia and Colocasia is that the Alocasia petioles (leaf stalks) continue as the main vein in the leaf blade, thus giving an arrowhead appearance with mainly upright facing leaves. Colocasia petioles do not continue into the leaf blade and the join is a definite elbow allowing the leaf to face downward.. Alocasia must have a free draining compost with ample water in warm to hot conditions, where as many Colocasia can be grown in a pond. Alocasia and Colocasia are not always easy to identify, as they hybridise easily, so you can never be totally sure that you are getting the plant you expect. Another problem with identification is that the young leaves may differ significantly in shape from the adult ones, so comparing a small plant with pictures of an adult may not give a match. The pictures on this page are correct as far as I can tell, but identification can be a minefield.
In American summer heat these can take lashings of water, but in the cooler maritine UK climate we have to be more careful, allowing the compost to dry a little at the surface between waterings, particularly in cool periods.
My experience of overwintering is that they are best kept going as if they go dormant are more difficult to restart than Colocasia, and take a full season to regain their original sized leaves. Keep above dormancy tamperature at 5C plus keeping on the dry side. . If the leaves show signs of wilting water from the bottom, standing the pot in a shallow dish of water for a minute or two
- The picture above show a mass planting of Colocasia esculenta, Fontanesii, Burgundy Stem, a yellow with red striped Musa sikkimensis, with Canna Indica, and Black Bamboo as the backdrop. with trailing Petunia to the front. To the right of the picture is a Black Hamburg grape. Picture taken at the end of August 2005.
For best effect plant out in groups of 4 to 5 plants. This mimics the natural clump forming habit of this type of plant. An idividual plant only has 3 to 4 leaves, after which they become very tatty and die off. This is natural, and not a cultural problem. The pictures you see of plants in more tropical climates are actually clumps of plants with up to 10 suckers.
In warmer climates, where temperatures are higher for longer this clumping forms naturally, but in cooler climates, and we are near the edge of its growing region, you need to give them a head start. A single plant will only have 3 to 4 leaves, whereas 5 plants in a group will have 15 to 20 leaves.
You cannot beat the effect of mass planting of these plants for that truly tropical look. To buy enough plants commercially, would be very expensive, so it is better to propagate your own.
I lift the plants before they are frosted, which here (Chalk) is mid to late October, or Early in Decmeber in 2006!, but it may be earlier elsewhere. Divide the suckers and pot them up into small pots in a well drained compost with the collar of the plant exposed. Keep root damage to a minimum. Also keep any runners on the plant to fully ripen, coiling around the inside of the pot.
The well drained bit is important for successful overwintering of some varieties, especially Black Magic, and small pots as the roots won't be agressively growing over the winter. Then place in a bright to sunny, frost free, place, 7C minimum for Black Magic types.. The plants will then grow, very slowly, over the winter. Keep dryish, and only water from the bottom by standing the pot in 1cm (1/2 inch) of water for a minute. This reduced the risk of rot setting in. Also remove any old leaf bases as these will turn to mush and promote rot. Air movement from open windows or a fan will also help to fight rot.
In the spring the plants will show visible signs of growth and should then be watered more frequently. Once growing strongly repot into larger pots or tubs in free draining but moisture retentive compost ready for planting out after the frosts.. This can all be brought forward by using bottom heat, giving bigger, more established plants.
Please see the Colicasia Propagation Page for full details of Sucker and Runner propagation.