Caladium bicolor is a tropical species also know as the elephant ear or heart of Jesus. It is cultivated for its brightly colored foliage, and there are more than 1,000 named cultivars--many are hybrids between C. bicolor and the closely related C. humboldtii. While caladiums are normally shade plants, new cultivars that tolerate full sun are now available.
Caladiums produce large, heart-shaped leaves between 6 inches and 2 feet long from tuberous roots. The leaves grow directly out of the tuber on long stems or petioles. They are brightly colored with red, pink, green, gray and white streaks, stripes and mottles. The leaf midribs and veins are often highly colored. Some cultivars have long thin leaves that are lance-shaped and some have arrow-shaped leaves. The small, green or white hooded flowers are inconspicuous and borne just above soil level. They produce small white berries.
The seven species in the Caladium genus are all native to tropical South and Central America. Caladium bicolor, the most widely cultivated species, is from Brazil and is also found in Trinidad and Suriname. Caladiums have become naturalized in many tropical and subtropical areas, including Florida and Puerto Rico.
Caladiums thrive in low light conditions under the canopy of tropical forests. They are often found along stream beds.
In USDA zones nine and above, caladiums can be grown outdoors all year-round but are vulnerable to all but the lightest frosts. They will thrive in a shaded spot in the garden in rich but well-drained soil and make good border plants when grown en masse. Caladiums require frequent watering, especially in dry areas. In colder and wetter regions, the tuberous roots can be dug up in the fall and overwintered in dry conditions at a temperature of no less than 50 degrees F. Replant stored roots after the last frost. Caladiums make good house plants but will lose most or all of their leaves during the winter. Water potted caladiums frequently but allow the soil to drain completely after watering; the roots are vulnerable to rotting. Plants can be stored in their pots in a cool, dry place with almost no watering.
Caladiums can be grown from seed but are normally propagated by division of the tuberous roots. Plants grown from seed may not grow to type. The roots should be divided just before they are replanted at the end of the winter. Each section of root should have at least two growth points of eyes.
Caladiums belong the Araceae family and like most plants in this family have high levels of calcium oxalate crystals in their leaves. These produce a burning sensation in the throat and mouth if ingested. High levels can be dangerous, causing swelling, nausea, diarrhea and even permanent kidney and liver damage. In severe cases, calcium oxalate poisoning can result in coma and death.