Plant of the Week
Jewelweed (Impatiens capensis)
By Kent Karriker
As its common name implies, jewelweed (Impatiens capensis) has a very beautiful flower. One of the sepals (outer parts of the flower) is modified into a large, pouch-like structure with a long spur, which gives the flower a pleasingly artistic shape. Its interesting shape, bright orange color, and decorative red-orange flecks make the jewelweed flower irresistible to people and pollinators alike.
A self-seeding annual, jewelweed typically grows two to five feet in height. It has weak, watery stems and alternately-arranged, oval-shaped leaves with toothed margins. Seedlings sprout in early spring and reach maximum size by August. Flowering begins in mid-summer and continues until frost kills the plant. The fruit is an elongated capsule, which, when ripe, bursts open at the slightest touch. Jewelweed resembles the closely-related pale touch-me-not (Impatiens pallida), which can be distinguished by its yellow flowers.
Jewelweed is a widespread and common plant that occurs in moist, semi-shady areas throughout northern and eastern North America. It often forms dense, pure stands in floodplain forests and around the forested edges of marshes and bogs. Jewelweed also colonizes disturbed habitats such as ditches and road cuts. It can be an aggressive competitor in its favored habitats, and is one of the few native North American plants that has been shown to compete successfully against garlic mustard (Alliaria petiolata), which is a non-native invasive weed that threatens many eastern North American forests.
The showy orange flowers of jewelweed must be cross-pollinated by insects or hummingbirds. However, jewelweed also has inconspicuous flowers that never open. These flowers (termed cleistogamous by botanists) fertilize themselves and produce seed without ever exchanging pollen with another flower. Cleistogamous flowers are very small (about 1 mm long) and are borne near the bases of the leaves. Research has shown that seeds produced by the showy, cross-pollinated flowers grow into larger, hardier plants, but the cleistogamous flowers produce seed at a much lower cost to the parent plant.
Jewelweed has a long history of use in Native American medicine. When applied topically, sap from the stem and leaves is said to relieve itching and pain from a variety of ailments, including hives, poison ivy, stinging nettle, and other skin sores and irritations. The sap has also been shown to have anti-fungal properties and can be used to treat athlete’s foot.
Jewelweed makes a lovely addition to native plant gardens that are located in moist, partially shaded areas. Not only are the flowers aesthetically pleasing, so are the hummingbirds, bumblebees, and butterflies that are attracted to the flowers. Jewelweed can be used to fill in empty spaces in the garden that might otherwise be taken over by non-native weeds. Jewelweed can be propagated easily by direct sowing of fresh seed in early fall. Once established, a patch of jewelweed will maintain itself through annual seed production.