Plant of the Week 01/30/2006: Double-flowered Impatience (Impatiens walleriana)

Plant of the Week 01/30/2006

Double-flowered Impatience (Impatiens walleriana)

Impatiens walleriana Hooker f.

Photographed by: Chelsie Vandaveer
Credits: Double-flowered impatience photographed in personal garden.
Other Information: Olympus C-8080wz

Busy Lizzy, patient Lucy, or simply, impatience (Impatiens walleriana Hooker f.) is a popular tender perennial planted for summer color in shady gardens. Easy to propagate from either seeds or cuttings, the plants are treated as annuals where winter temperatures are cold. Impatiens, with somewhere around six hundred species, comprise the majority of the family Balsaminaceae. From temperate to tropical, there are species found in Europe, Asia, North America, and Africa.

The flowers typically have a flat face with the petals imbricate—overlapping like shingles. A spur extends from the back. But not all of the 'petals' are petals. One of the sepals forms the spur and the uppermost petal is actually a colored sepal. The stamens and pistil are hidden under a calyptra or hood that sits like a nubbin at the center. An insect visiting the flower must negotiate between the lowest two petals to reach the nectar in the spur; in doing so, it brushes against the stamens and pistil under the calyptra.

Impatiens received their name from the fruit, a capsule. When the seeds are ripe, the capsule dries, its five valves stretched like elastic. The capsule, now under tension, explodes at the slightest touch flinging the seeds several feet from the parent plant.

Busy Lizzy was found growing on rocks in a stream in Mozambique in 1868 by John Kirk, an explorer with David Livingstone, and Horace Waller, a missionary. Specimens were sent to Joseph Dalton Hooker in London, but the plants were not introduced to gardeners until the late 1890s. Since that time, gardeners, breeders, and horticulturalists have created thousands of varieties with colors ranging from white through every shade of pink and magenta to oranges and reds.

Double-flowered varieties happened as chance mutations during efforts to mass produce types that would not come true from seeds. But in becoming doubles, the flowers lost the ability to produce seeds.

(Compiled from: Hortus Third, Staff L.H. Bailey Hortorium, NY State College of Agriculture and Life Sciences, Cornell University, Macmillan, NY, 1976; A-Z Encyclopedia of Garden Plants, C. Brickell and J.D. Zuk, eds., American Horticultural Society, DK Publishing, NY, 1996; "Balsaminaceae", Watson, L., and Dallwitz, M.J. 1992 onwards. The families of flowering plants: descriptions, illustrations, identification, and information retrieval, Version: 23rd October 2005; Plant Varieties Journal, Vol 16, No 1, 2003, Department of Agriculture, Fisheries, and Forestry, Australia; and W3Tropicos, Jim Solomon, VAST Nomenclatural Database, Missouri Botanical Garden.)