Impatiens capensis Meerb.

Spotted jewelweed, jewelweed

Spotted jewelweed is a North American native plant. Im­patiens means “impatient,” a reference to the fact that dried seed capsules burst open when touched. Capensis means “of the cape,” because the botanist who named it, Nicolaas Meerburgh, believed incorrectly that the species was native to the Cape of Good Hope in Africa. The plants are common and, in some areas, invasives.

Plants: 3–5′ (1–1.5 m) high, with translucent and rather fragile stems.

Leaves: Bluish-green, oval-shaped, with shallow teeth, about 4 ⨉ 1¾″ (10 ⨉ 5 cm).

Flowers: Flowers occur in clusters of one to three. Viewed from the side, flowers are shaped a bit like a horn of plenty, yellow, with two large lower petals and one upper petal, with spots or patches of red-orange. Each flower is about ¾″ (1.9 cm) in size. They may appear orange rather than yellow from the front.

Fruits: The seed pods, about ¾–1¼″ (1.9–3.2 cm) long, spread their seeds by drying into a spring-loaded form that pops upon contact, delighting children.

Habitats: Regions that are at least seasonally wet and partially shaded, such as creek beds or damp soils. Spotted and yellow jewelweed prefer similar habitats and are often found close to each other.

Medical: Spotted jewelweed has long been used as a preventative for poison ivy rash. Juice from the crushed plant is applied to the site that has been exposed. We examined many articles to learn a bit more about its efficacy:

• Some sources suggest that the crushed stems are best; others that stems, leaves and flowers can all be crushed together. If you have a choice, use stems only, from plants that haven’t flowered yet.
• The juice extract can be prepared in the field simply by rolling and crushing a handful of jewelweed between the hands, then applying the sap to the exposed skin.
• Spotted jewelweed is uniformly considered to be much more effective than its close cousin, yellow jewelweed.
• Most advocates believe that the jewelweed extract needs to be applied relatively quickly—within four hours, prior to the development of poison ivy blisters—but a few insist that it is helpful even when applied to blisters.
• Controlled studies sometimes confirm jewelweed’s effectiveness, but not always.
• Everyone agrees that poison ivy is often found in places where jewelweed is present (for example, both occur in my back yard). But poison ivy also grows in places where jewelweed cannot, so there is no guarantee that you can find it.
• Jewelweed extract can be included as an ingredient of soaps, available commercially; or frozen into ice cubes and saved for later.
• Lawsone, a red-orange dye, may be the active ingre­dient that has antihistamine and anti-inflammatory effects.

What do we believe? It certainly won’t do any harm: there aren’t any reports of allergic reactions to jewelweed. So, given that spotted jewelweed is fairly often found near poison ivy, and that it is easy to prepare by rubbing between the hands, it is worth a try.

Similar species.

Online References:

References:

Older scientific or horticultural names

Impatiens capensis description by Thomas H. Kent, not updated.

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