Few if any plants are more popular than caladiums for brightening shady spots in Southern gardens. These tropical American natives are grown not for their flowers, but for their marvelous foliage: large (to 112 feet), long-stalked, heart- or arrow-shaped, often almost translucent leaves colored with spots and blotches of red, rose, pink, white, silver, bronze, and green. Caladiums are excellent both as bedding plants and in containers.
Hybridizing has produced three classes of caladiums: fancy leaf, lance or strap leaf, and dwarf. All caladiums grow best in bright-shade locations, with 24 hours of direct sun per day. A number of dwarf hybrids will tolerate full sun.
Most selections sold at garden centers are fancy-leafed types, typically reaching 2 feet (occasionally to 4 feet.) tall and wide. Popular choices include 'Aaron' (white with green edges); 'Candidum' (white with green veins); 'Carolyn Whorton' and 'Fannie Munson' (pink with crimson veins); and 'Freida Hemple' (red with green border). These and other older selections need shade, but many newer ones have thicker leaves that tolerate part sun; examples include 'Celebration' (white with red veins and green edge); 'Fireworks' (red with green border); 'Moonlight' ('Florida Moonlight') (white with a very thin green edge); 'Party Punch' (pink with light pink spots and green edges); 'Pink Beauty' (pink with green speckles and edges); 'Rose Glow' (pink with green border); 'Tapestry' (white with pink veins and green edge); and 'White Cap' (white with white veins and green edges). Sun-tolerant selections include 'Raspberry Moon' (light green with red splashes); 'Red Flash' (green with red center and veins and pink spots); and 'White Queen' (white with red veins).
Strap- or lance-leaf caladiums produce large bunches of leaves. Most stay under a foot tall; some grow considerably taller. All tolerate sun and are useful as edging or in mass plantings. Recommended selections include 'Candyland' (green with white veins and heavy splashes of pink); 'Florida Red Ruffles' (intense deep red with a uniform green edge); 'Florida Sweetheart' (rose with green edges); 'Heart's Delight' (red with mottled light and dark green edges); 'Lance Whorton' (pink with red veins and green edges); 'Pink Gem' (salmon pink with dark salmon veins and green edges); 'Red Frill' (red with green edges); and 'White Dynasty' and 'White Wonder' (pure white with green edges).
Dwarf caladiums have small leaves but grow about as tall as fancy-leafed types. Two of the best are 'Gingerland' (white with red spots and green edges) and 'Miss Muffet' (lime green with burgundy spots).
Caladiums grow best in rich soil, high humidity, and heat. They won't tolerate soil cooler than 60F and are likely to rot if planted too early in spring. Gardeners wanting to get a jump on the season can start caladiums indoors in pots, then transplant them to the garden. In most winters south of the I-10 corridor, the tubers can remain in the ground all year if provided with a generous layer of mulch (plants die down completely in winter). Elsewhere, dig and store them in fall, or grow the plants in pots and bring them indoors for winter.
To grow in the ground, plant tubers in spring when nighttime temperatures are consistently above 60F. Plant them knobby-side up, 12 inches deep, spaced 612 inches apart. Keep well watered and feed lightly with water-soluble fertilizer several times during the growing season, or apply a controlled-release fertilizer once in spring. When foliage begins to look ratty in late summer or fall, cut it back. Where freezes are likely, dig tubers and remove most of the soil from them; then dry them for several days in a shaded, dry location and store in dry peat moss at 5565F until planting time in spring.
To grow in pots, start tubers indoors in late winter or outdoors in spring. Plant 2 inches deep in well-drained potting mix to which you've added controlled-release fertilizer; space just an inch apart for the best display. Water thoroughly.