Take a walk along a shady pond side, river bank or wetland area this time of year and you’re likely to encounter clusters of plants with odd-shaped, singly-borne, bright orange-yellow pendulous flowers – that’s jewelweed! In fact, jewelweeds often grow in such dense clusters that their canopy can suppress or shade out the establishment of perennial herbs. Although there are multiple species of jewelweed, the most common one we have on Cape Cod is spotted jewelweed (Impatiens capensis). Spotted jewelweed can be distinguished from pale jewelweed (I. pallida) by the flower color and shape; spotted jewelweed flowers are a darker orange-yellow color, are often speckled with dark brown spots, and have a long, bent-back rear spur, while pale jewelweed flowers are pale yellow and have a short, right-angled rear spur. 

Jewelweed leaves, as seen from above.

Spotted jewelweed is an annual, meaning it reproduces solely from seed each year. But it is a prolific seed producer, and actually has two different methods of pollination. The first is through cross pollination. Spotted jewelweed flowers are considered complete flowers, in that both male and female parts are present in a single flower. However, the male flower parts develop and decline before the female parts within the same flower ever mature. This differential timing helps to ensure cross-pollination. Although each flower only blooms for a few days, the plant will continue producing new flowers throughout the summer. The flowers are pollinated primarily by bees and wasps, but also serve as an important nectar plant for the ruby-throated hummingbird. But jewelweed also produces special cleistogamous flowers, which are small, green, inconspicuous flowers that never open and are entirely self-pollinated. Stands of jewelweed in dense shade or drier soil tend to rely more heavily on these self-pollinated cleistogamous flowers. The result is that these two methods give spotted jewelweed various growth options and an abundance of seeds.

Both open flowers (large orange flower to the right) and cleistogamous flowers (small light green flower at the top left) are present on jewelweed plants. 

The seed dispersal mechanism of spotted jewelweed is also quite effective, as well as entertaining. Next time you walk by a patch of jewelweed, touch one of the seed pods and watch the seed capsule curl up on itself and fling the seeds some distance away from the parent plant. This action gives spotted jewelweed its other common name, “touch-me-not,” due to the fact that the seed capsules spring open and catapult the seeds away when touched. Interestingly, the expelling force of the seed capsule is dependent on whether the pod developed from a cross-pollinated open flower or a closed, self-pollinated cleistogamous flower. Seeds from the open flowers are flung farther than those from closed flowers. Scientists hypothesize that this likely results in higher success for future generations of jewelweed since self-pollinated seeds are more likely to thrive in conditions similar to their parent site (nearby), while cross-pollinated seeds would be more likely to survive in conditions potentially different from their parent site (farther away).

In addition to uniquely shaped flowers and entertaining seed ballistics, spotted jewelweed is also a useful plant. The juice from the stems and leaves provides relief from skin rashes and insect bites. Applying a poultice made from jewelweed to poison ivy or poison sumac rashes will reduce inflammation and relieve the itching. In addition, applying jewelweed to the skin immediately after being exposed to poison ivy or poison sumac may also help neutralize the rash causing oils. Spotted jewelweed is also edible. In the spring, the young shoots and leaves can be eaten as a cooked green (like spinach). The seeds are also edible and are beginning to be available now. They taste a lot like walnuts, but due to their small size, they are not practical for much more than an occasional trail nibble. There’s also the challenge of trying to contain the seeds in your hand while the seed pod is attempting to fling them elsewhere.

A seed pod curled open after attempting to disperse its seeds and the two seeds I managed to contain during the dispersal.