Saturday, January 30, 2010

Fancy Leaf Caladiums

For a colorful, tropical appearance in your garden, plant caladiums.  Their flashy, heart- or lance-shaped leaves will brighten the darkest corner of the garden.  Masses of caladiums will compete with any flower bed for a vivid display.

Caladiums are aroids, members of the Araceae family along with anthurium, pothos, monstera, philodendron, calla and jack-in-the-pulpit.  The botanical name is Caladium bicolor or C. x hortulanem.  Common names include "Angel Wings", "Elephant Ears", and "Heart of Jesus."  Many aroids are native to the tropics.  Caladiums are native to South America, particularly the region in and around Brazil.  They are cold-hardy in the United States from USDA climate zone 9 through 11.  Those who live in cooler regions can grow them successfully as annuals in landscape beds and container gardens.  Most gardeners, however, lift and store the corms over winter.

These fancy plants are available in a wide range of color patterns, usually in shades of red, pink, green and white.  Those structures often referred to as flowers are not actually flowers at all, but are modified leaves called spathes.  The actual flowers are much smaller and are surrounded by the spathes.  The spathes, however, are relatively insignificant.
Caladiums are grown from corms.  A corm is a thick, bulb-shaped stem or stem base that grows just below the soil surface.  Roots grow from the bottom of the corm.  Shoots and leaves appear at the top.

They are often considered to be useful only in the shade garden.  Certainly, they are perfect for shady areas.  But many cultivars grow very well in full- to partial sun.  If planting in the garden, select a site with richly organic, moist but well-drained soil.  Soil pH should be between 5.6 to 6.5.  The best way to determine if the pH is within that range and contains the proper nutrients for caladiums is to have the soil tested.  Your local Cooperative Agricultural Extension Service can help you.  You can collect the soil sample yourself.  For a nominal fee, they will send your soil sample to a laboratory for analysis.  Be sure to call the Extension office for instructions.

Prior to receiving your corms, cultivate the soil to the depth of 8 inches and add plenty of well-rotted compost.  Remove weeds.  Soil test results may recommend other soil amendments.  Follow those instructions.  If you use synthetic fertilizer, allow at least a week before planting so it can be incorporated into the soil by rain or irrigation and not burn the corms.  The site should be ready for planting when your caladiums arrive.

Bear in mind that all parts of the plant are toxic if eaten and can cause skin irritations and/or allergic reactions in sensitive persons.  I've never experienced such a reaction to caladiums, nor do I know of anyone who has.  But, if you believe you might be susceptible, wear gloves when handling them.

Caladium corms can be planted in spring when soil has warmed to 65 degrees Fahrenheit.  The question I am most often asked is "Which end is up?"  If your caladiums are not yet sprouting, look for small growing points.  These may be encircled by fine fiber:  the remains of last year's leaves.  The bottom may have coarser fibers arranged in no particular direction:  the remains of last year's roots.

Some caladiums, particularly the taller cultivars, may produce too few stems and foliage if planted in shade.  To produce more leaves, they may benefit from "de-eyeing."  To "de-eye" the corm, rub off visible buds or "eyes" with your finger.  This will cause the corm to produce more buds and result in a bushier plant.
Plant the corms 2 inches deep and space them approximately 6 to 8 inches apart.  After planting, water well.  If some of the soil washes away, replace it.  Then water sparingly until growth appears.  With warm soil, roots and shoots should begin to form soon.   A light layer of straw mulch will help to preserve moisture and suppress weeds.

During summer, you may fertilize occasionally.  Apply 2 tablespoons of 10-10-10 fertilizer per ten square feet of garden area every two weeks until leaves appear.  Do not allow synthetic fertilizers to come into contact with the plants.  Irrigate if rainfall is inadequate.  Soil should be kept slightly moist.  Weed when necessary, but be careful not to disturb the corms.  Occasional application of a recommended insecticide will keep leaf-eating insects away, though the extent of their damage is usually minimal and cosmetic.  Call your Cooperative Agricultural Extension Office for insecticide recommendations.  Always, follow label instructions.

Growing caladiums in containers is not much different than in the garden.  A 6" pot will accommodate 3 corms nicely.  Use the finest potting soil; cheap soil will give poor results.  The best potting soils will be light-weight, peat-based with added materials to enhance plant growth.  Select containers that will accommodate the corms and any other suitable companion plants.  All companion plants should have similar soil and moisture requirements.  Because container gardens can dry quickly, take steps to keep the pots properly watered.  Adding moisture retentive gel to the soil can be beneficial.  Larger containers are not as susceptible to drying.  Tipping over can also be a problem with small containers.  Caladiums can grow to 24" in height, though dwarf varieties have been developed.

You may use caladium leaves as you would fresh cut flowers. Cut the leaves at least 3 hours before arranging them. After cutting near the bottom of the stem, immediately set stems in water. They will wilt at first, but will freshen up after a bit.  Arrangements should last for 2 to 3 weeks.

When the growing season is nearing its end, let the foliage remain to build reserves in the corms for the next growing season.  You may remove the foliage when it has turned yellow.

If you live in a climate zone where caladiums are not cold hardy, you may dig and store them until the next growing season.  Do so when temperatures drop to about 65 degrees F.  After digging them, remove foliage, wash the corms and let them dry in the shade.  Pack in peat moss and store in boxes or bags with some ventilation.  Plastic bags with ventilation holes like potatoes come in will do nicely.  Store in a dark place where the temperature can be maintained between 55 and 60 degrees F.  Moisture should not collect in the storage container.  Neither should the corms be allowed to become bone-dry.

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