Jennifer Schultz Nelson
Extension Educator, Horticulture
If you are looking for something to brighten up a shady spot in your landscape, consider Caladiums. Their brightly colored leaves streaked in shades of green, white, red and pink in various stripes and spotted patterns attract a lot of attention. It's another one of those plants that has the dangerous potential of being one I'd like to collect because of the astounding number of different cultivars available.
If you bought a cultivar each day, you would easily still be buying plants for at least three years, as there are over 1000 named cultivars of Caladium bicolor, the cultivated plant descended from the original seven species of Caladium native to Brazil and the surrounding region. They are divided into two major groups–the fancy-leaved and the lance-leaved cultivars. The fancy-leaved types are the most popular, with large, colorful leaves, standing about 12 to 30 inches tall depending on the cultivar. The lance-leaved cultivars have narrow, but colorful leaves, and a more compact growth habit.
Historically, Europeans have been cultivating Caladium since the 1700's, when they were a novelty brought back from exploration of the "New World". Intense plant breeding, selecting for different leaf coloration has led to extremely high numbers of cultivars today.
Caladium are in the family Araceae, which also contains the closely related genera Alocasia, Colocasia, and Xanthosoma. Often these plants are all referred to by the common name Elephant Ear. Lesser known common names for Caladium are Angel Wings and Heart of Jesus.
While using the name Elephant Ear for multiple genera of plants may be confusing, they do all hint at another reason people like to grow these plants–large leaf size. You may assume leaf size is related to cultivar, but it surprised me to learn it is more related to tuber size.
Caladiums and all the other Elephant Ears grow from a knobby, starchy tuber. A good quality tuber is firm and has several buds along the surface. Tubers are graded by size, and larger tubers produce larger leaves. Mammoth grade tubers are 3 ½ inches and up, Jumbo are 2 ½ to 3 ½ inches, No. 1 is 1 ½ inches to 2 ½ inches, and No. 2 is 1 inch to 1 ½ inches.
If you look at a Caladium tuber that has just begun to sprout, you'll notice a large central bud surrounded by several small buds. If you want to have fewer, but the largest leaves possible for that particular tuber, leave the central bud intact. If you would like more leaves, but slightly smaller ones, use a sharp knife to remove that central bud.
Removing the central bud allows the smaller buds to grow. The central bud produces a plant hormone that suppresses growth of the smaller side buds. Removing the central bud removes the suppression and the smaller buds can grow.
It is also possible to take a large Caladium tuber and cut it into smaller pieces to generate plants with smaller leaves–remember leaf size is dictated by tuber size. This relationship of leaf size to tuber size probably has something to do with the energy stored in the tuber. More stored energy equals larger leaves.
Despite the tuber holding stored energy for the Caladium, they still need regular fertilization during the summer. There are many suggestions out there for fertilizer regimens specific to Caladiums, but a balanced fertilizer is really all you need. If I had to mix up specific fertilizer ratios for each plant in my garden, I would never get the job done! Better to apply a balanced fertilizer while fertilizing the rest of your garden than to not fertilize Caladiums at all. Be cautious though, as too much fertilizer can burn the leaves. Without fertilizer their colors can fade. Also, too much sun can fade colors.
Although there are some Caladium cultivars out there that can tolerate sun better than others, none tolerate full sun all day. Most will do best in dappled to moderate shade. If they are in too much shade, their color will suffer, and often leaves will appear mostly green.
Moist, warm, fertile soil is essential for Caladiums. As with many plants, a soil rich in organic matter produces the best plants. They also prefer moist, but not soggy soil, growing best in moist soil at temperatures above 70 degrees Fahrenheit. If the soil is too cold, the tubers will rot rather than sprout. Many gardeners start Caladiums indoors in order to control the temperature and get a head start of the season. Also, you can often find Caladiums already growing at your local garden center, usually in with the annuals.
Being tropical in origin, Caladiums are annuals in most parts of the U.S. With a little care, they can be overwintered indoors. Tubers should be dug up and brought indoors as the foliage begins to die, which usually happens as daily air and soil temperatures decrease in the fall. The leaves should be removed from the tubers only after they have completely dried, and ideally tubers are stored in dry sphagnum moss or vermiculite where temperatures do not fall below 60 degrees Fahrenheit.
Unfortunately, this means storing Caladium tubers in an unheated garage is not an option, as it will get too cold. Temperatures below 55 to 60 degrees Fahrenheit will damage and likely kill Caladium tubers. This damage shows up first as a spongy soft tuber–something to keep in mind when selecting tubers to purchase.
With a little luck your Caladiums will survive to see another growing season. If you, like me, hate to dig plants out of the garden to overwinter them, consider planting your Caladiums in pots. That way you can bring the whole pot indoors, no digging required. Ideally you should remove the Caladiums from the pots, but if they are allowed to dry properly, they may even manage to survive in the pot over the winter.
Some cultivars will grow well indoors as houseplants, so that is another option. Of course, you can always treat Caladiums as annuals and allow them to die off and replace them with new selections next spring. As much as I hate to let a plant die that I could somehow overwinter, I don't have space to bring everything indoors to grow for the winter. If nothing else, treating Caladiums as annuals allows you to try different cultivars each year.