If you live in the northern half of the U.S., you may think caladiums are only suitable for southern gardens. Not so! The photo below was taken in a zone 6 garden in New Jersey, where caladiums put on a great show every summer.
Caladiums are actually even more versatile in the North than they are in the South. In areas where the sun is less intense, caladiums don’t need to be restricted to shady locations. Many varieties will tolerate almost any light conditions, from full shade to full sun.
Caladiums, like canna lilies, calla lilies and elephant ears, grow from tubers. This means the plants start the growing season with a ready supply of stored food energy. As soon as the tubers begin growing, they grow with remarkable speed.
Here are a few tips and tricks to help you get the most from these easy summer-blooming bulbs:
Start with large, grade #1 caladium tubers rather than the smaller, #2 or #3 sizes. The bigger the tubers, the more stored food energy the plants will have available to fuel their growth. Longfield Gardens sells only #1 caladium tubers.
Don’t be too eager to plant your caladium tubers because they will not grow in cold soil. Plant the tubers only after the soil temperature has warmed up to 65°F. In the central U.S. this will be sometime around Memorial Day. In northern areas you may need to wait until mid-June.
For a quicker display of color, caladium tubers can be pre-sprouted indoors. Start them about 4-6 weeks before you will be moving them outdoors. Plant the tubers in barely moist growing mix and keep them warm (70-75°) day and night.
Caladium tubers are usually planted approximately 6" apart. Another alternative for northern areas is to plant groups of 3 or more tubers, spaced just 3 to 4" apart. At the start of the season, these clumps will have a bigger presence than single plants that are evenly spaced.
Even in the north, it’s best to protect caladiums from harsh midday sun. Dappled light beneath shade trees, or morning or afternoon sun, will bring out their richest colors. The most sun tolerant caladium varieties are Carolyn Whorton, White Queen, Red Flash, Aaron, Florida Cardinal, Florida Sweetheart and Rosebud.
Caladiums grow well in pots and planters. Soil temperatures are usually higher in a container and caladiums appreciate that extra heat. In northern areas where the soil temperature may not reach 70°F until June, planting caladiums in containers will give the tubers a big head start.
Caladiums are tropical plants and the tubers will not survive cold winters. The plants also need a long growing season in order to develop large, plump tubers. If you live in USDA zones 3-7, it's best to simply treat your caladiums as annuals. There is no need to dig them up at the end of the growing season as the tubers will disintegrate over the winter.