Monday, July 27, 2015

Jewelweed: Definitely Not A Weed

JewelweedBy definition, a weed is any plant growing where you don’t want it. To clarify, this holds true only in the garden beds or acreage under your cultivation. “Weeding” flowers in a park planter because they offend your sense of aesthetics is frowned upon.

To a plant, having “weed” embedded right in its name is probably akin to having a “Kick Me” sign on your back. Right out of the box there is bound to be a bit of prejudice against you, fair or unfair. Spotted knapweed, goutweed and Japanese knotweed are all pernicious invasive species, and deserve all the bad press they get. But occasionally an innocent bystander suffers from this name game.

The native plant commonly known as jewelweed (Impatiens capensis) is one of those exceptions. A succulent plant that thrives in rich moist soils, it is is nearly always welcome no matter where it is found. It’s an annual that is just as happy at the edge of the Arctic Circle as near the equator. Jewelweed has dappled orange, cornucopia-shaped flowers that attract hummingbirds and humans, though not necessarily for the same reason.

Hummingbirds and butterflies have been sipping nectar from its blossoms for who-knows how many millennia. While early settlers began dragging it back to north and central Europe as an ornamental beginning in the 1700s, native peoples have valued it for thousands of years. Jewelweed may be unique in that it is at once a visual treat, a tactile diversion and a medicine.

Jewelweed is sometimes called touch-me-not, which might suggest one shouldn’t touch it. On the contrary, it should be handled. Jewelweed is “armed” with projectile seeds, and if you touch a mature seed capsule it will burst with surprising force, strewing seeds in all directions. Touching touch-me-nots is an activity that can amuse children (and some of us who never grew up) for long periods of time.

Poison ivy and jewelweed aren’t friends, but they like the same habitat and seem to have reached a certain rapprochement. Toxic urushiol oil in poison ivy produces dermatitis in most people and a severe allergic reaction in some, but urushiol is neutralized by jewelweed sap. Jewelweed’s thick jointed stem is easily crushed, and you rub this juicy pulp over the skin where poison ivy has contacted it. It helps relieve itchiness caused by insect bites and nettles as well.

Although its reputation as a treatment for poison ivy and other rashes goes back centuries in oral traditions, jewelweed sap has not been well investigated for this purpose in controlled trials. However, the sap has been used to treat athlete’s foot and other fungal conditions, something which does have has a basis in science — research has confirmed that jewelweed is antifungal.

A close relative of the ornamental impatiens varieties that we love for shady areas, jewelweed is not susceptible to impatiens downy mildew, a disease that has destroyed traditional impatiens in the past few years. Perhaps the key to developing resistant impatiens lies with jewelweed.

Its name may come in part from the way its leaves sparkle when held under water. The leaves are hydrophobic, not wettable, and myriad gemlike air bubbles adhere to them when submerged. It’s possible, too, that it was dubbed a jewel because of its important medicinal uses. Now if we could just get rid of the “weed” portion of its name.

Photo courtesy Wikpedia user Ram-Man, some rights reserved.


Paul Hetzler

Paul Hetzler is the Horticulture and Natural Resources Educator at Cornell Cooperative Extension of St. Lawrence County.

You can reach Paul at the Cornell Cooperative Extension office in Canton at (315) 379-9192.




9 Responses

  1. What a lovely article about a favorite plant of mine. I am one of those child-like adults who delights in seeking out jewelweed just to pop the seed capsules. Milkweed is another beautiful and useful plant that gets a bad rap with “weed” attached to it’s common name. Maybe another article on this beauty?

  2. Terry DeArmas says:

    Would you be able to tell me what are the criteria for determining whether a plant is invasive and who makes that determination? I know recently NY published a list of invasive plants that are no longer available for sale in NY. I am the volunteer invasive plant coordinator for Indian Lake under the auspices of RIPP.

    Thanks. Terry DeArmas

  3. Paul Hetzler Paul Hetzler says:

    Holly, a milkweed article an excellent idea. Interesting that I just got a call from someone wondering if we have a milkweed restoration program (answer: no). Fortunately milkweed is easy to get established.

    Terry, to be considered invasive, an organism must 1) be from a distinctly different ecosystem; 2) be able to establish themselves and spread effectively; and 3) cause significant environmental and/or economic harm, and/or be a threat to human health. The USDA maintains a list, as does every state. However, any jurisdiction is free to define additional invasive species within their borders if conditions warrant it.

  4. Curt Austin says:

    Thank you for asserting the rights of all peacefully-abiding plants, their status as weeds notwithstanding. I authored a photo book of flowers some years ago; I was guilty of discriminating on the basis of color, but not origin.

  5. Charlie S says:

    I have these plants in my breezeway that sprout pretty yellow flowers ever year come summer.I don’t know what they are but my neighbor insist their weeds and were it up to her they’d be chopped to pieces by now.I like plants and bees and butterflies like flowers and so I let them grow.I have a hard time killing any thing.

    Ralph Waldo Emerson described a weed thus: ” A plant whose virtues have not yet been discovered.”

  6. Paul Hetzler Paul Hetzler says:

    Curt, good to hear from another “weedophile.” Is your book still in print?

    Charlie, what a great definition of a weed! Thanks.

  7. Charlie S says:

    Hi Paul…Thank Ralph Waldo. I thought it was a great definition also.Makes a lot of sense. A plant is a plant and to me there’s no such thing as a weed,which is more or less an unwanted plant.

  8. Bruce says:

    Traveling between 2400′ elevation at my home, and 3200′ at the Blue Ridge Parkway, the Jewelweed changes colors from what we might consider the “normal” orange shade, to yellow. Orange lower down, yellow higher up.

    Other flowering plants seem to have an altitude component as well. Along the Parkway, Trillium seem to be mostly white, while in the valleys purple is fairly common.

  9. Paul Hetzler Paul Hetzler says:

    Interesting that there’s an altitude correlation between orange jewelweed and yellow, which is actually a separate species, Impatiens pallida.