Jewel Weed Lessons

– This article, by Dick Fisher, first appeared in WildfloraRI, Winter 2022

As the natural forces of the world escalate with strong wind, drought, floods and the like, it is comforting to experience a gentler side, one which has persisted continually for millennia. It would be difficult to find a more fragile relationship than the hummingbird/ jewelweed bond. Jewelweed (Impatiens capensis), a native annual, precariously dangles its flower, bouncing with the breeze, on a string two centimeters long. The hummingbird, its chief pollinator, hovers fleetingly to access nectar in an elegant midair dance.

Jewelweed prefers wet areas near streams or boggy areas, where it will grow up to five feet tall with succulent hollow stems.  It will grow in drier areas or respond to drought conditions by being proportionally shorter. Flowers are produced all summer from the axils of alternate leaves along a zigzag stem. The leaves have coarsely serrated margins and are covered with fine hairs that shed water. The orange- yellow flowers are cone-shaped with a terminal spur and hang on a two- to three-centimeter stalk. The flower develops from three petals and three sepals into a horn-shaped nectar sac. A knob of five anthers forms above it. In what has been called ‘tandem ripening’ the anthers release pollen for just 24 hours and then are shed. To prevent self-pollination the pistol then forms and receives pollen for just four hours. It’s another type of special dance, this time to promote generic diversity. In addition to hummingbirds, bees, butterflies, and hawkmoths have been noted as pollinators.

Being an annual, jewelweed has to do it all in one season: grow, develop reproductive organs, become pollinated, and mature and scatter its seeds to prepare to begin the process anew each year. Unlike perennials, which can wait out the winter with underground root systems, annual plants must be able to produce and germinate viable seed year after year.

Jewelweed has developed some instructive ways to bolster sustainability, and we can just hope they will be enough to adapt to the changing environment. Its fertilized ovum becomes a one-centimeter long dangling slender pod containing three to five seeds. When ripe, if the stalk is touched, it will suddenly split open, flinging the seeds far and wide, which accounts for one of its common names: ‘touch- me-not.’ The seeds are covered with a thin capsule, which when rubbed off, reveals the shiny blue seed; hence, the other common name, ‘jewelweed.’ The seeds germinate in April and May, producing a thick colony of new plants. The duration of seed viability has been reported to be short, so how long they will remain in the seed bank to bridge stressful years is in question.

But jewelweed has an important adaptation to unfavorable conditions such as we have seen during the dry summer of 2022. That is cleistogamy, a mechanism by which flowers under stressful conditions do not fully form but remain closed and are able to self-pollinate to produce viable seed. This saves the plants valuable energy since they produce only a small amount of pollen and no nectar. The inconspicuous blossoms form on the lower portions of the plant in the leaf axils. Jewelweed uses this trick when conditions are dry or if the plant has been cut back or grazed.

There are two species of jewelweed in the Northeast: Impatiens capensis Meerb, spotted jewelweed, which is orange with reddish-orange spots, and I. padilla Nutt., or pale jewelweed, which has yellow blossoms and is found in more shaded areas. They have an overlapping range and share pollinators, but it is thought that their pollen is incompatible and so they remain genetically distinct. There is currently an iNaturalist citizen science project underway to determine the comparative range of the two species. I. capensis seems to dominate in this area, and the descriptions here are from those populations. Medicinal properties are attributed to the liquid sap from the succulent stems, which is claimed, when applied to the skin, to reduce the itch from poison ivy, nettle, eczema and hives, and to treat fungal infestations in feet. A concoction including crushed flower buds mixed with rum is claimed to treat open wounds and burns.

There were three populations of spotted jewelweed growing in damper areas of our small property, which were doing wonderfully in 2019. During the dry summer of 2020 one of the populations withered in mid-summer and did not obviously flower. I don’t know if cleistogamous flowers were present but in the wet summer of 2021, this population did not return; the others did. During this past very dry summer of 2022, that population again did not return while the other two started out looking normal but faded in mid-summer with few if any blossoms. One population, although looking sparse, has produced some seed pods and the mid-September rains might be helping. It will be interesting to follow jewelweed populations as the drought/ flood climate pattern continues, to determine if jewelweed’s safety systems will be enough to sustain it and the multiple organisms it supports.

Will it be the canary?

 

References

Capon, Brian. 2005. Botany for Gardeners.,Timber Press, Portland, OR.

Del Tredici, Peter. 2010. Wild Urban Plants of the Northeast. Cornell University Press, Ithaca, NY.

Kaczmarek, Frank. 2009. New England Wildflowers., The Globe Pequot Press, Guilford, CT.

Moerman, Daniel E. 1998. Native American Ethnobotany. Timber Press, Portland, OR.

Schottman, Ruth. 1998. Trailside Notes: A naturalist’s companion to Adirondack plants. Adirondack Mountain Club, Lake George, NY.