Caladiums for Florida¹

R.J. Black and B. Tjia²

Caladiums have been grown in Florida for their colorful foliage for many years and they continue to be popular landscape and container plants (see Figure 1). Whether grown in a container, in beds or as border material, caladiums add color and dimension to the landscape all summer long for very little cost and maintenance.

Figure 1. Caladiums can be effectively grown in Florida.

Caladiums (Caladium hortulanum) are members of the Araceae family and are tropical American in origin, with many of them coming from the Amazon basin in Brazil. Caladiums available to Florida gardeners at local nurseries, garden supply dealers and chain stores are predominantly hybrid cultivars developed through years of plant breeding.

Caladiums will grow profusely year round in central and south Florida. In northern Florida, use as a perennial is somewhat limited by low temperatures during the winter months. However, caladiums can be effectively grown in north Florida when the tubers are dug, cleaned and stored in the fall, and replanted in late spring.

There are two types of caladiums available - fancy leaved and lance or strap leaved. Fancy-leaved caladiums are the more popular type. Large colorful somewhat heart-shaped leaves are characteristic of this type. The distinguishing characteristic of the lance-leaved type is a narrow, elongated leaf. The length of the leaves is similar to the fancy-leaved type but the plants are usually more compact. Lance-leaved caladiums are hardier and lend themselves for use in flower arrangements because of their lasting quality as cut foliage.

The size of caladium plants is indicated by tuber size. Large tubers will produce plants with large leaves. Tubers are grouped into grades according to size: Mammoth - 3 1/2 inches (9 cm) diameter and larger; jumbo - 2 1/2 inches (6 cm) to 3 1/2 inches (9 cm); No.1 - 1 1/2 inches (4 cm) to 2 1/2 inches (6 cm); and No.2 - 1 inch (2.5 cm) to 1 1/2 inches (4 cm).

Selection

There are numerous caladium cultivars available in a wide choice of colors. Table 1 is presented as a guide to cultivars which are known to perform well in Florida.

Caladiums can be purchased as tubers, seedlings or full-sized plants in the spring from nurseries or garden supply dealers. Tubers should be inspected closely for firmness. Soft, spongy tubers should not be purchased as this usually indicates that the tubers have been damaged by cold temperatures (below 60°F {15°C}). Full-sized plants can be left in the container and used indoors or on the patio or removed from the container and planted in the landscape.

Selection of Planting Site

Caladium tubers are grown commercially in south central Florida under full sun. Growing under full sun most of the day fades colors, although it is not detrimental to the plant. Caladium tubers produce larger and more intensely colored leaves in partial shade. They should be planted in the landscape where they receive filtered sun or direct morning sun for three to four hours a day. Caladiums should not be planted in heavily shaded areas because plants will stretch and develop weak petioles.

Caladiums should never be planted under eaves of buildings without guttering. Heavy rain falling from an eave will seriously damage caladium leaves. Heavy rains will also damage leaves when caladiums are planted on bare soil. Splashing water combined with loose particles of sand rasp leaves and cause injury. A mulch of some kind is therefore necessary to protect against rain injury.

Planting and Care

Caladiums grow best on high organic, well aerated soil. To obtain these soil conditions it is generally necessary to amend sandy soils with organic matter. Some sources of organic matter include peat moss, well rotted manure and compost.

If started from large tubers, caladiums can be grown in unamended poor soil for at least one season because there is enough food stored in the tuber to last one season. Tubers grown in unamended poor soil should be discarded and replaced annually.

Tubers can be planted directly into ground beds after danger of frost is past. They should be planted the last part of February in south Florida, the middle of April in the central peninsula, and the first of May in the northern peninsula and panhandle. Tubers should be planted two inches (5 cm) deep and 18 inches (45 cm) apart with growing points facing upward. Firm the soil around them when planting to prevent the formation of air pockets between the tuber and the soil.

Caladiums grow best in a moist, well drained soil. Overwatering in poorly drained soil will cause fleshy tubers to decay. Wilting occurs rapidly if soils are allowed to dry. Foliage loss is likely if plants remain wilted.

Proper fertilization produces healthy, large-leaved plants. When grown in organic soils, spread 1/2 tablespoon of a complete fertilizer around each plant or 1 lb. per 100 square feet of bed area four to six weeks after planting and every two months during the growing season. Plants grown in sandy soils will benefit from monthly applications during the growing season, because fertilizer is rapidly leached from sandy soils.

Growing Caladiums in Containers

Caladiums make colorful and compact pot or tub specimens. Caladiums grown in containers or planters should be started from tubers rather than from seedlings. Seedling caladiums require too much time to make large specimens, although they are the least expensive initially. If tubers are used, four to six weeks are required for them to develop into full-sized plants.

When it is desirable to have a large container filled with plants, plant several small tubers in the container rather than one large tuber. If small tubers are unavailable, large tubers can be used (Figure 2). Remove the center bud to allow more smaller side shoots to develop or cut the tuber into 3 to 5 pieces. If one or several large plants are desired use the largest tubers and do not remove the center bud.

Figure 2. Preparation of caladium tubers for planting. (A) Removal of the central bud will force the tuber to produce many small shoots and leaves. (B) Cutting the tuber into sections will also force the production of many small shoots and leaves. (C) Planting the entire tuber will produce a plant with a few large leaves.

Caladiums can be grown indoors as container plants provided the proper cultivars are selected. Some caladium cultivars which tolerate indoor conditions include 'Lord Derby,' 'White Christmas,' 'Fire Chief,' 'Red Flash,' 'Carolyn Whorton,' 'Poecile Anglais,' 'Sea Gull,' 'Scarlet Beauty' and 'Aaron.'

Storage of Tubers

Caladiums cannot tolerate cold temperatures, and when soil temperatures drop below 60°F (15.5°C), plants will gradually deteriorate, and finally the foliage will die. This is essentially what happens in the fall in north Florida. The yellowing and drooping of the foliage signals the time to dig and store caladium tubers (Figure 3). They should be dug before the leaves completely deteriorate because leafless tubers will be difficult to locate.

Figure 3. Digging and storing caladium tubers. Tubers should be dug in north Florida when the foliage begins to yellow and droop. They should be lifted from the soil, cleaned, dried and stored in dry peat moss or sand in a dry, well ventilated area at a minimum temperature of 70°F (21°C).

It is not necessary to dig and store caladiums in south Florida because they usually continue growing most of the year. In central Florida there is enough cold temperature during the winter to cause death of the foliage. However, tubers do not have to be dug since soil temperatures usually do not drop low enough to injure them.

Tubers should be lifted from the soil, cleaned of soil particles, and dried. Pack the dried tubers in dry peat moss or sand and store in a dry, well ventilated area at a minimum temperature of 70°F (21 °C). Do not allow temperatures to exceed 90°F (32°C) or fall below 60°F (15.5°C) for prolonged periods of time. Tubers gradually lose moisture and shrink at temperatures above 90°F (32°C). Storage temperatures below 60°F (15.5°C) result in physiological breakdown of the tubers. Storing tubers in unheated garages where temperatures during the winter months can drop to 40°F (4.5°C) or below will result in cold-damaged tubers.

Tubers will usually begin to sprout after eight weeks of storage. They are ready to plant at this time, however, they can be held in storage and planted in the spring.

Insects, Nematodes and Diseases

Insects are not generally troublesome on caladiums. Occasionally aphids and thrips may become a problem. The most serious insects on caladiums are chewing insects such as caterpillars, which chew leaves, making the plant very unsightly. Observe plants carefully and if insects are detected, apply the appropriate insecticide at once to insure beautiful plants all summer.

Caladiums can be damaged by nematodes, and plants grown in the same area year after year have a greater chance of infestation. When an infestation builds up, move caladiums to another area or treat the soil with nematicide before planting.

The most common disease of caladiums is tuber rot. It occurs when tubers are stored or held at temperatures below 60°F (15.5°). Chalking or dry rot of tubers is another disease problem which frequently occurs in storage, yet does not seem to be too detrimental to the tuber.

Tables

Table 1. Fancy-Leaved Caladiums

Pink-Leaved Caladiums
Fannie Munson -	Bright hot pink, scarlet ribs, green border
Rosebud -	Deep frosty rose, light green border
Pink Cloud -	Variegated pale green, pink border
Pink Beauty -	Splotchy pink, deep pink veins
Mrs. Haldeman -	Bright pink leaf, green edge
Miss Chicago -	Flushed pink, white and red veins
Lord Derby -	Transparent rose colored leaf, green edge
Kathleen -	Light salmon pink, green border
Carolyn Whorton -	Multcolored leaves, very fine pink
Dr. Groover -	Bright pink splotched leaf with green edge
Red-Leaved Caladiums
Freida Hemple -	Heavy-leafing, low-growing, red
Postman Joyner -	Outstanding dark red
Red Ensign -	Brilliant metallic red
Red Flash -	Red with pink spots, green border
Crimson Wave -	Crinkled transparent crimson
Festivia -	Transparent red colored leaf
Fire Chief -	Crimson red, heavy leaf
John Peed -	Bright metallic red
Poecile Anglais -	Heavy-leafing, low-growing, red
Red Flare -	Scarlet leaf, blotched
Ruby Smith -	Crimson red, large leaves
Blaze -	Red scarlet ribs, low growing
Scarlet Beauty -	Brilliant scarlet, low growing
Jorchy -	Heavy-leafing, low-growing, red
White-Leaved Caladiums
Candidum -	White leaf, green rib
White Christmas -	Heavy leaf, solid white, green veins
Seagull -	Green leaf, white ribs
Aaron -	Creamy white center, narrow green border
Ivory -	Creamy ivory to lemon and lime
June Bride -	Transparent white, light green shades
Mrs. Arno Nehrling -	Off-white shaded coppery red, crimson ribs
Lance-Leaved Caladiums
White Wing -	Creamy white, green border
Rosalie -	Shiny red leaf, green border
Blue Gem -	Bluish green leaves
Pink Symphony -	Exotic silvery pink, green border
Pink Gem -	Deep pink, green border
Caloosahatchie -	White narrow leaf with pink and green

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Footnotes

1. This document is Circular 469, Department of Environmental Horticulture, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. First printed: September 1979. Reviewed: June 1997. Revised September 2003. Please visit the EDIS website at http://edis.ifas.ufl.edu

2. R.J. Black, associate professor, B. Tjia, associate professor, Department of Environmental Horticulture, Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, 32611.

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