Ivy-leaf geraniums have an entirely different character than their zonal geranium cousins. Long, trailing stems make them ideal for containers of all kinds. Their flowers are generally less strident and more toned to the pastel range of their hues. Older varieties are somewhat intolerant of long periods of heat and humidity, but newer varieties are more heat-resistant. The common name springs from the shape of the leaves.
Description of ivy-leaf geranium: Two distinct groups of ivy-leaf geraniums are available to home gardeners. All of them have the cascading form of ivy geraniums, but a group of single-flowered varieties from Europe are proving more floriferous and heat-tolerant. Semi-double flowered varieties have less bloom, but still make real impact all summer. Many varieties are available -- from miniatures with a spread of only 12 inches through vigorous ones that can grow to 5 feet tall.