For Release On Or After 06/01/12
By Dan Gill
LSU AgCenter Horticulturist
Gardeners crave color in shady areas of their landscapes just as much as they do in sunny areas. Unfortunately, shade-loving plants are generally not so flamboyant, and the selection of colorful bedding plants for shady gardens is limited. Thank goodness for caladiums. Even in fairly heavy shade they can be counted on to provide color through the summer.
Modern varieties are primarily derived from Caladium bicolor and its hybrids with other caladium species and are grouped under the name Caladium x hortulanum. Caladiums belong to the Arum family, which provides us with many tropical landscape plants and houseplants.
Caladiums are grown for their attractive foliage, which is produced from knobby, brown tubers gardeners often call bulbs. The 6-to-12-inch, heart-shaped leaves emerge from the ground on arching stems that are generally 1 to 2 feet tall. The foliage may be splashed with combinations of white, pink, rose, red, burgundy, chartreuse or green, often with several colors combined in wonderful patterns. These bright leaves with their bold texture embellish our shady gardens from May until October when the tubers go dormant. They are remarkably free from major insect or disease problems and thrive in hot, humid weather.
Caladiums grow best in shade to part shade (two to four hours of direct sun, preferably in the morning). In these conditions they produce lush growth with large, colorful leaves. Some varieties are tolerant of sunnier conditions and are successful in beds that get part to full sun (six hours or more of direct sun a day). But avoid hot and dry locations.
Caladium plants you purchase at nurseries are usually grown in shady greenhouses, and the foliage will often scorch or burn if you plant them into beds that receive too much direct sun. This results in brown areas and holes literally burned into the leaves. If the variety is sun-tolerant, new foliage will emerge adapted to the sunnier conditions.
You can buy caladium tubers now and plant them directly into well-prepared beds. By now some nurseries have caladium tubers on special sales at a good price, and because our growing season is so long, it’s not too late to plant them. Caladium plants are also available growing in 4- to 6-inch pots. They will provide immediate color in the landscape and grow larger and more beautiful through the summer. Whether you choose tubers or growing plants, space them 8 to 12 inches apart when you plant them.
Careful bed preparation will ensure healthy, robust plants. Turn the soil in the area to be planted, and then incorporate a 2- to 4-inch layer of organic matter such as compost, rotted manure or peat moss. Next, lightly sprinkle the area with an all-purpose fertilizer following package directions, and rake it into the upper few inches of the soil. As an alternative, a little slow-release fertilizer can be placed around each tuber as it is planted into the bed.
Caladium plants should be planted with the top of the root ball level with the soil of the bed. Plant unsprouted tubers about 2 inches below the soil surface. You should see growing points or even pinkish-white sprouts on the knobby side of the tuber. That side is planted up. The smoother, rounded side is the bottom of the tuber.
Once the tubers or plants are in the ground, mulch the bed with 2 inches of your favorite mulch and water them in. Keep caladium beds well watered during the summer, especially those receiving lots of sun.
The colorful, tropical foliage of caladiums combines beautifully with impatiens, begonias, torenias, liriope, ferns, achimenes, gingers and other shade-loving plants. They are generally more effective when a single color or variety is used in a bed or landscape. If several colors are used, they are most effective when masses or groups of each color are used together in the planting.
In late September or October, cooler temperatures encourage caladiums to go dormant. When grown with poor growing conditions, particularly in areas of deep, heavy shade, the plants will likely produce small, weak tubers that may not return well the following year whether left in the ground or dug and stored. Under the right circumstances and with proper care, however, the tubers you planted this summer can be dug in the fall and planted next April. Or they can be left in the ground to provide a beautiful display again next year and for years to come.
All types of caladiums thrive here planted in partly shaded locations. The variety you choose is a matter of taste. The LSU AgCenter Hammond Research Station has been evaluating the sun tolerance of caladium varieties. The most recent results from 2011 indicate the following varieties performed best in sunny locations: Fire Chief, Elise, Carolyn Whorton, Moonlight, White Queen, Lance Whorton, Rosemary, Candyland, White Delight, White Dynasty, White Wing and White Wonder.
Rick Bogren