Caladiums are as much a fixture in the summer landscape as bedding begonias and impatiens. Landscapers and gardeners plant them en masse in shady borders and fill big containers with their bright colors and bold markings.

Often, caladiums are a better option than some flowering annuals because, if treated properly, they provide big color until fall and they are not marred by snails, slugs and sowbugs.

This spring there is news in the caladium world. New hybrids are greatly expanding the colors and patterns. Dallas-based Abbott-Ipco added a Florida caladium farm to its operations several years ago to develop and propagate new hybrids from tissue culture. The company had enough inventory to release 11 new varieties this spring to growers, landscapers and retailers and plans to add four to six more next year. Up to 150 new caladiums are under development for Abbott-Ipco.

"Nobody's introduced any new caladiums in quite a while," says Richard Hollander, whose father started the family business by importing spring-blooming bulbs from Holland. "We were seeing a decline in the vibrancy of colors, more diseases, more susceptibility to stress." The company opted to grow its own inventory, propagating tubers via tissue culture. The result, says the younger Mr. Hollander, is caladiums that are tougher and healthier.

The most striking plants include several whites, always a popular choice in Dallas-area gardens and used to brighten dark shade under mature trees. 'Moonlight', for one, is a broad, all-white leaf with the tiniest edging in green. 'Mount Everest' is a tall white that can be used in the middle of the border. 'White Marble' is a white strap-leaf hybrid.

'Raspberry Moon', watermelon-red on chartreuse, and 'Twist and Shout' with pinky-brown splotches on bright green also have been popular with retailers, says Mr. Hollander. He cautions, however, that availability is limited this year as the company builds inventory.

Hines Horticulture also introduced new caladium hybrids. Its offerings are inspired by the new so-called Thai caladiums that have been trickling into the U.S. market via mail-order garden retailers. Thai caladiums, as the story goes, were developed for the sole use of the royal family, and anyone else was forbidden to plant them. Their leaf colors, including chocolate and maroon, are a departure from the pinks, reds and whites Americans have relied on for decades of annual shade color in summer.

The Thai Delights collection from Hines features 10 new hybrids with names including 'Thai Dye' (white and magenta), 'Hot Wasabi' (chartreuse and red), 'Wild Orchid' (almost brown) and 'Jades of Color' (bold green veins on pink-tinged white leaves).

Mr. Hollander recommends planting the tubers after Mother's Day.

"The caladium is a tropical bulb that wants nothing, nothing , to do with cold. Not cold soil, cold temperatures, cold water," says Mr. Hollander. Cold makes a caladium "weaker, stresses out the bulb and causes them to come up short, come up sporadically, come up small."

A stressed tuber, he says, may not hold up to summer's onslaught of heat and dry conditions. If you hold off planting them until mid-May, he says, "it pays off when we get to 100-degree days."

The new Hines caladiums won't even be in stores until the week of June 9, when they will be sold in quart pots, already leafed out, and not as loose tubers.

Mr. Hollander also emphasized that fancy-leaf caladiums can take some direct sun, contrary to the popular notion that they must be planted in full shade.

"If you've got morning sun but afternoon shade, that's perfect," he says. Even strap-leaf varieties, which were developed to take sun, won't stay attractive if they are not watered often at the height of summer.

All caladiums like well-drained soil, frequent watering and a thick, loose mulch to help keep their roots cool.

•Abbott-Ipco hybrids are at:

Calloway's, multiple locations

Mike's Garden Center, Dallas, Arlington, Southlake and Fort Worth

North Haven Gardens, Dallas

•Hines' Thai Delights won't be in stores until after June 9. Retailers include:

Calloway's, multiple locations

Classic Gardens, Murphy

Covington's, Rowlett

Jackson's Home & Garden, Dallas

Hare's Nursery, Arlington

North Haven Gardens, Dallas

Plant Market, Dallas

Strong's Nursery, Carrollton

Twin Oaks Nursery, Denison