Caladiums for the Landscape
Caladiums are tropical foliage plants, discovered within the Amazon basin of Brazil. Now, widely grown for their colorful leaves, they are used as pot, border, and bedding plants. Mass plantings are used to create a focal point in the landscape. Colorful caladiums provide a striking contrast with the green foliage of other plants, especially when caladiums are planted in the foreground. Count on caladiums to provide summer color in shaded areas where sun-loving flowers won't grow.
Fancy- and strap-leaved varieties are the two main types of caladiums and are distinguished by leaf size and shape. Fancy-leaved types have large heart-shaped leaves, grow best in semishade, and may reach a height of 12 to 30 inches, depending on variety and growing conditions. The strap- or lance-leaved types have narrow, elongated leaves and perform best as accent plants in borders, in hanging baskets, and in patio planters.
Varieties exhibit combinations of shades of red, pink, or white, with prominently colored midribs and contrasting backgrounds and borders. The variation in leaf color and pattern provides many uses for caladiums in the landscape.
Nurseries and garden centers offer caladiums as potted plants or dormant tubers. Tubers are available in four different sizes based on diameter and are priced accordingly. Tuber sizes are classified as mammoth, 3.5 inches and up; jumbo, 2.5 to 3.5 inches; No. 1, 1.75 to 2.5 inches; and No. 2, 1.25 to 1.75 inches. Large tubers have more leaf buds than small tubers and, therefore, make larger and better displays.
Caladiums require a warm, moist soil to grow. A minimum soil temperature of 70 degrees Fahrenheit is preferred. Planting in cool soil results in slow growth or tuber rot. A good rule of thumb in determining when to set out caladiums is to plant them when you plant okra seed in the vegetable garden.
Each caladium tuber has a large central bud surrounded by several small buds. Most caladium varieties produce only a few colorful leaves if the large central bud is allowed to grow. Its presence prevents the small buds from growing and producing leaves. The small buds are encouraged to grow when the large central bud is removed before planting the tuber in a process called “de-eyeing.”
Commercial caladium plant producers do this, and so can gardeners. Hold the tuber with four fingers and leave your thumb free to remove the large, central bud. It should snap off fairly easily if the tuber is heathy. Deeyeing also reduces flower production, which some gardeners prefer. Caladiums have traditionally needed protection from full sun for best growth and color, but some of the newer varieties tolerate exposure to full sun for a couple of hours daily. See variety descriptions at the end of this information sheet.
For best growth, plant caladiums in porous soil that contains plenty of organic matter, with a pH between 6.0 and 6.5. Peat moss or other organic materials such as compost can be used to increase the soil's organic matter content and decrease soil pH. Plant tubers 2 to 3 inches deep and, depending on their size, 8 to 12 inches apart. At planting time, incorporate a complete nursery special fertilizer into the soil at a rate of 1 to 2 pounds per 100 square feet of bed area. Follow this with 1 pound of fertilizer each month during the growing season. Make proportional reductions in amounts of fertilizer for smaller areas. Do not allow fertilizer to contact the caladium leaves. Water thoroughly after fertilization to prevent fertilizer burn.
Mulch caladium plants when they are established to keep the soil moist and cool. Soil temperatures over 85 °F can result in leaves with more green color and less of the highly prized brilliant colors. High levels of nitrogen fertilization can produce the same effect.
Most caladium plants will produce flowers during the growing season. The presence of the greenish-white flowers slows production of the colorful leaves, and flowers should be removed as soon as detected.
Caladiums can be treated as annual plants and left in the garden at the end of the season to be killed by cold weather. However, it is possible to save caladium tubers for planting again the following year. At the end of the growing season, but before the leaves have lost all color and before soil temperatures drop below 55 °F, dig the tubers that are to be saved, retaining the foliage, and sort them by color or variety. Spread them out in an area protected from rain and cold, and allow them to dry for a week. Cut or pull the dry foliage from the tubers and remove all dry soil. Place the tubers in a mesh sack and store them where the temperature does not fall below 60 °F.
Diseases of Caladiums
Tubers may decay when in storage or during the growing season. Several organisms cause tuber rot. Bacteria cause a soft rot and slimy decay, while fungi cause a dry and chalky rot. Select disease-free tubers for planting. Store tubers properly to avoid high humidities and cool temperatures. Never store caladium tubers in the refrigerator. Tubers purchased in early spring, before ideal planting time, should be held at room temperature.
An anthracnose fungus has been found to attack caladiums, and lower leaves may develop light tan-to-brown spots. Generally, the disease is not severe enough to warrant chemical control. Remove diseased leaves as they appear.
Burning of the margins of older leaves and scorching of leaves usually are the result of foliar application of fertilizer, watering during the hot part of the day, or a lack of water.
Preparation of caladium tubers for planting
Planting the entire tuber will produce a plant with a few large leaves.
Removing the central or dominant bud(s) will allow the tuber to produce many small shoots and leaves.
Table 1. Caladium Varieties for Mississippi Landscapes
|Aaron||white with green margin some sun tolerance|
|Candidum||white with green veins|
|Florida Fantasy||white with red veins|
|June Bride||white with green margin|
|Marie Moir||whitish green with red spots|
|White Queen||white with red veins, some sun tolerance, more red with shade|
|Carolyn Whorton||pink with red veins and green margin|
|Fire Chief||dark pink, limited sun tolerance|
|Pink Beauty||pink, lighter than Fannie Munson|
|Pink Cloud||pink, green margins, some sun tolerance|
|Gypsy Rose||pink veins with green blotches|
|Freida Hemple||deep red (lighter than Postman Joyner) with green margins, no sun tolerance|
|Kathleen||red with green margin|
|Postman Joyner||dark red with green margin|
|Red Flash||dark red, fuchsia spots, green margin, good sun tolerance|
|Rosebud||red with green margin|
|Caloosahatchee||white with green margin|
|Candidum Jr.||dwarf white with green vein|
|Gingerland||white with red blotches and green margin|
|White Wing||white with green margin|
|Florida Sweet Heart||mauve pink with green margin|
|Pink Gem||pink, excellent for basket|
|Pink Symphony||pink with green veins|
|Lance Whorton||red with white blotches and green margin|
|Red Frill||red, excellent for basket|
|Rosalie||red with green margin|
|Miss Muffett||dwarf green with white veins and red blotches, no sun tolerance|