OF THE WEEK
Dr. T. Ombrello - UCC Biology Department
Busy Lizzy, Patient Lucy, Patience Plant, Sultana, Zanzibar Balsam, Impatiens
Scientific name: Impatiens Wallerana (formerly Impatiens sultanii)
Explanation of scientific names:
- from Latin, referring to the sudden bursting of the ripened pod like
fruits when touched
- commemorates Waller
sultanii - commemorates the Sultan of Zanzibar
Wallerana is one of over 500 species of Impatiens in the Balsam
family (Balsaminaceae). The
genus Impatiens has practically a world-wide distribution, with members
ranging from the tropics and subtropics of Asia and Africa to the temperate
zones of North America. Close
relatives of Impatiens Wallerana with which a gardener
might be familiar would include the old fashioned annual Garden Balsam (Impatiens
balsamina) and the 2 common wildflowers called Jewelweeds or Touch-me-nots
(Impatiens capensis and Impatiens pallida).
Impatiens Wallerana is native to East Africa. Its center of origin is Zanzibar, but it also grows naturally from Tanzania to Mozambique. The plant grows as a succulent herb to a height of about 3 feet. It thrives in rich moist soil and prefers a shaded or semi-shaded location. It is a perennial in its native habitat, but since it cannot tolerate frost it is grown as an annual in this country. Flowers are one to two inches across and come in a variety of colors, including carmine, pink, reddish-orange, purple, white, and variegated (a combination of white and some color). An interesting floral feature is the slightly curved nectar spur protruding down from the back. The nectar spur produces and contains a sweet sugary solution that attracts certain animals to serve as pollinators. Moths and butterflies, with their elongated tube-like mouthparts, can reach the sweet nectar in the Impatiens flower spur and are the primary pollinators of the genus. Hummingbirds can also be found visiting the flowers.
Impatiens fruit is a capsule which, when mature, contains cells with a high
internal pressure (turgor pressure). In
addition, the ripened fruit has structurally weak cells found in specific
locations. This combination of high
pressure and weak cells allows for the slightest jarring of the plant to cause
the fruit to "explode", shooting the seeds several feet from the
parent plant. This insures good
seed dispersal and lessens the chance of an overcrowded seedling population
developing around the parent.
Impatiens Wallerana has long been available to the gardener
as a flowering annual that will tolerate shade, it was never popular until the
mid 1960's. Varieties available before then did not flower consistently,
and plants grown from a seed packet produced everything from dwarfs to vigorous
but tall and lanky plants. Many
produced more stems and leaves than flowers.
in the mid 1960's, plant breeders focused considerable time and attention to
hybridizing and selecting Impatiens Wallerana.
As a result of their efforts, there are currently dozens of cultivars
available with a wide range of plant size and flower color.
They flower early and continuously through the growing season and are
tolerant of heat. Some cultivars
can even grow in a full sun location. Primarily
due to these new introductions, the popularity of Impatiens has increased
future for Impatiens looks even brighter. In
1969, the U.S. Department of Agriculture and Longwood Gardens sponsored a plant
collecting expedition to New Guinea. The
plant explorers literally stumbled across some new species of Impatiens with
larger flowers, more intense color, interesting leaf patterns of variegation,
and tolerance to bright sunlight. These
new species, however, were tall and lanky in habit, dropped their lower leaves
early in life, and flowered sporadically. Other
plant explorers found similar species in Java and the Celebes Islands of
none of these new species could be interbred with the Impatiens commonly grown
in this country, the new species could be crossed with each other.
The USDA in Beltsville, Maryland and Longwood Gardens in Kennett Square,
Pennsylvania initiated breeding programs with these "New Guinea
Impatiens". Since then,
promising breeding lines have been released to seed companies and commercial
plant propagators. They, in turn,
have introduced them to the general public.
These “new” Impatiens have become increasingly popular with home
gardeners. While some New Guinea Impatiens can be grown from seeds, as
are Impatiens Wallerana, the offspring tend to be quite
variable, with little uniformity. For
that reason, New Guinea Impatiens are propagated primarily from cuttings, making
them more expensive. Plant breeders
are actively working on the development of consistent, seed-grown New Guinea
Impatiens. They are probably only a
few years away from being released.
Impatiens, in general, are the most popular bedding plants in the United States, and will undoubtedly remain so for many years to come.
A flower on an Impatiens Wallerana plant growing in one of Union County College's greenhouses.