General Discussion & Chat: Tropicals: Elephant Ear bulbs, 1 by PlanterRik

PlanterRik wrote:
To start with, it's useful to note the difference in genus. This thread has been mainly about Colocasias, and you are asking about an Alocasia. Different species of Colocasia can require very different situations to thrive, and Alocasias vary even more widely. Alocasia macrorrhiza is one of the most popular and easiest to care for. It's cell structure is denser than most Colocasias, and the leaf surface is somewhat glossy, while most Colocasias have a matte surface. Both of these differences result in its maintaining moisture within the plant better and longer. It is less prone to drying out, and when it does get dry, it will recover more quickly with less foliage loss.

The other side of that coin is that overwatering and poor drainage can be more of a problem than with Colocasias. Many Colocasias are grown as marginals -- around the edges of ponds or even in shallow water. If the water is very well oxygenated, some Alocasias might grow as marginals, but I haven't tried it.

For general care, I would recommend rich soil that is very well drained. In pots, I start with a good quality potting soil, add perlite and very fine, slightly composted bark that is sold as "soil conditioner." The fine, composted bark can also sometimes be found as "organic growers base." It has the consistency of coffee grounds. In addition to helping with drainage, the bark decomposes slowly, releasing nitrogen and other nutrients. I use, roughly, two parts potting soil, one part fine bark, one-half part perlite. You can add a time-released chemical fertilizer (balanced or specialized for foliage plants). You could also add composted manure (I use about a half cup to a cup per gallon of pot size). I use both, plus a liquid fertilizer. That probably sounds like too much, but these tropicals really respond to it.

Many people add Ironite to supply micronutrients. If you have access to earthworm castings, they are very good for establishing a healthy bacteria and micro-organism population in your soil. You could also just put a few earthworms in each pot. I make a point of putting worms in pots of elephant ears because rotting elephant ear roots are one of their favorite foods. So, if you should have a little rhizome rot (and who doesn't?), the worms will clean that out and prevent it from spreading and rotting the whole plant.

I think they do best in partial shade. They are often grown in full sun, but I think their foliage is a richer green and the surface keeps a nicer gloss, and the plants hold more leaves in 50-70% shade. If they are not getting enough light, the stems will become long and weak and will not be strong enough to hold the leaves up.

Variegated Alocasia macrorrhiza is becoming more available now, and it is a beautiful plant. Here is a small one I had on my landing among my coleuses and other small ears last year.