Growing Caladiums in the Landscape
Caladiums provide spectacular color and a tropical ambiance for the home or commercial landscapes. Because they are available in very diverse plant sizes and leaf shapes, the gardener can use caladiums for different purposes and areas in the garden. For example, the strap leaved cultivars, with their short compact plant size, make ideal border plants. When planted in hanging baskets, their lance leaves trail gracefully from the container. The Fancy-leaved types have relatively large leaves and can be used as accent plants or for a magnificent display of color as the focal point in the landscape.
Shade or sun
One important aspect of caladiums is that they provide color in shady locations. Caladiums thrive under oak or other shade trees where it is almost impossible to grow most flowering plants. Since they perform so well in a shady landscape, it is commonly thought that all caladiums require low light to grow well. However, there are cultivars that will perform well in partial shade and full sun, and some examples are: fancy-leaved cultivars ‘Aaron’, ‘Candidum Jr.’, ‘Carolyn Whorton’, ‘Florida Elise’, ‘Florida Fantasy’, ‘Pink Cloud’, ‘Red Flash’ and strap-leaved cultivars ‘Florida Red Ruffles’, ‘Florida Irish Lace’, ‘Florida White Ruffles’, and ‘Florida Sweetheart’ and ‘Pink Gem’. The limiting factor when growing these sun tolerant cultivars in direct sunlight is water. When caladiums are stressed from lack of moisture, the leaves will appear as if the sun has burned them, but the cause is really due to the plant drying out.
Caladiums prefer a high organic soil although they can grow in sandy or heavy loam soils if irrigation and drainage is managed properly. Sandy soils can be amended with peat moss or compost and the soil covered with a heavy layer of mulch after planting to help retain soil moisture. For clay or loam soils which retain too much moisture, addition of peat or compost will help provide aeration to the soil. If the soil is excessively wet, drainage may need to be provided, or the beds can be raised slightly to provide an area for the caladium roots to grow above the saturated soil.
Selection of tubers
Caladium tubers are packaged or sold by size based on tuber diameter: Mammoth, greater or equal to 3 ½ inches; Jumbo, 2 ½ to 3 ½ inches; No. 1, 1 to 1 ½ inches; and No. 2, 1 to 1 ½ inches. For a dazzling, quick display of large leaves, Jumbo and Mammoth tubers are the best. These work well in climates with short growing seasons, or when instant color is desired. The smaller tubers require longer to attain their maximum potential, and may be chosen by the more patient homeowners with a longer growing season (Southern states).
When and how to plant tubers
Caladiums are tropical plants and require temperatures above 60° F to flourish. Thus, it is critical to wait to plant caladiums until temperatures are 60° F or above. Tubers should be planted upright with 1 to 2 inches of soil covering the top of the tuber. Use of potted (bedding plants) caladiums: Caladiums may be purchased as bedding plants in 4 to 6-inch pots to be transplanted into the landscape.
As plants sprout, which generally takes 2-3 weeks, application of a low rate of a slow-controlled release fertilizer will provide adequate nutrition for the growing season in most areas of the country. Alternatively, monthly application of a soluble complete fertilizer, such as an 6-6-6, at a rate of 2 lbs per 100 square feet will help plants to continue to produce large colorful leaves during the growing season. As with tubers, it is necessary to time planting to coincide with warm temperatures. Temperatures should be above 60° F or plants will not establish well. Soil requirements, fertilization and irrigation practices are the same as described for tubers.
Caladiums must be irrigated frequently. If they dry to the wilting point, caladiums may initiate a dormancy phase. Plants may not resume growth, or grow poorly, even after being watered if stressed long enough. On the other hand, caladiums thrive during rainy periods when many flowering crops perish.
Some gardeners desire to save their caladiums from one year to the next by digging tubers. When temperatures begin to drop below 60° F, caladiums will start to loose leaves. If a severe cold front moves through the area, and temperatures fall below 50° F for a few days, it is time to dig the tubers. Tubers need to be removed before soil temperatures drop below 50° F . In general, the growing conditions and the length of the growing season prevent tubers from increasing in size. Rather, they use up their storage reserves and thus are smaller and less vigorous than freshly purchased tubers. However, some are successful at carrying over tubers for several years. Tubers must be stored above 60° F and preferably at 70 to 75° F.