Slippery Elm – Ulmus rubra

Overall At-Risk Score: 34

Latin Name:

Ulmus rubra (Muhl.); previously Ulmus americana; syn. Ulmus fulva¹

Common Name:

Slippery Elm; Red Elm, Moose Elm, Soft Elm

Family:

Slippery Elm; Red Elm, Moose Elm, Soft Elm

Geographic Region:

U. rubra is found in much of eastern North America:  AL, AR, CT, DE, FL, GA, IA, IL, KY, LA, MA, MD, ME, MI, MO, MS, NC, NH, NJ, OH, OK, PA, RI, SC, TX, VA, VT, WI, WV, IN, it is also found in the Canadian provinces of Ontario and Quebec

Habitat:

Found mostly in rich, riparian forest³ understories.⁴

Lifespan:

As a small understory tree, U. rubra has a shorter lifespan than larger tree species.

Reproduction:

Flowers emerge in late-winter or early-spring in the form of small clusters green, hair flowers⁴. These flowers become circular winged-seeds, and usually drop by late-spring

Ability to withstand disturbance and over harvest:

This small understory tree often benefits from tree-fall disturbances opening the canopy. Due to Dutch Elm Disease, there are very few mature Slippery Elm trees left in nature. Harvesting currently healthy trees for lumber or bark, could remove disease resistance from the gene pool.

Status of Endangered/Threatened(by state):

A species of “Special Concern” in Rhode Island, and is believed to be extirpated from Maine.²

Part of Plant Used/Active Medicinal Compounds:

The bark of U. rubra is harvested for the mucilage produced by the cambium layer. Often taken orally to treat a variety of digestive issues and sore throats, though there is little evidence supporting the gastrointestinal benefits studies have shown an effectiveness in soothing inflamed throats.⁵

Vulnerability of habitat/changes of habitat quality and availability:

The prefered habitat, floodplains, has historically been a target of development from towns and channelization. This has limited the current habitat quality for U. rubra and continues to do so. Though urban development, agriculture, and logging are depleting available habitat for the Slippery Elm, the biggest threat to U. rubra populations is the long-lasting damage done by Dutch Elm Disease.

Demand and Relative Acreage Needed to Meet Demand:

 

Wild Harvesting Impact On Other Species:

 

Recommendations for industrial and home use:

Due to the declining wild populations of U. rubra it’s important to not use any wild-harvested bark. There are many alternatives to this widely used herb, Marshmallow (Althaea officinalis), Comfrey (Symphytum sp.), and Mullein (Verbascum sp.) are just a few.

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SOURCES:

  1. Ulmus rubra.
    https://www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=19050#null
  2. USDA Plants. Ulmus rubra
    https://plants.usda.gov/core/profile?symbol=ulru
  3. New England Wildflower Society. Go Botany. Ulmus rubra
    https://gobotany.newenglandwild.org/species/ulmus/rubra/
  4. http://www.museum.state.il.us/muslink/forest/htmls/trees/U-rubra.html
  5. Medline Plus. Slippery Elm.
    https://medlineplus.gov/druginfo/natural/978.html


Slippery elm is truly one of the most versatile plants in the herbal kingdom. An important “tree of plenty”, it is renowned for its beauty, medicine, and food; it seems to help everything it touches. Its herbal actions are demulcent, expectorant, emollient, diuretic, and nutritive in nature. Slippery elm has a long history of use as an herbal medicine; it is still listed as an official drug in the United States Pharmacopoeia and is also sanctioned as an over-the –counter drug. It is one of nature’s best demulcents, its effectiveness proven through eons of use. It contains mucilage cells, starch, tannin and calcium oxalate. These constituents penetrate and cover exposed irritated surfaces, aiding in the healing process. Having an emollient action, it tends to soften and relax inflamed tissues and is specific for inflamed conditions of mucous membranes of the bowels, stomach, throat, and kidney.

Propagation and Cultivation

Given the current status of the elm population in general, along with the incredible usefulness of slippery elm, it is imperative that we begin planting this tree as a part of our sustainable farm and garden practices, much as we plant comfrey and Jerusalem artichokes. Though slippery elm is still susceptible to Dutch elm disease, it remains healthy and usable for the first several years of its life. Thick young stands of trees could be thinned and used as medicine, while older, more disease-susceptible trees could be used for building and firewood. These plantings should not only be considered for aesthetics, and for food and medicine, but also as a source of seed stock to ensure the future survival of this most giving tree.

Slippery elm seeds may be sown as is in their normal cycle in the spring of the year, in an 18-inch raised peat moss soil and sand bed. The beds may need wire top for protection of the young seeds and seedlings. You can expect a 10 to 25 percent germination rate. Transplant the trees into tree tubes within the first month of germination (the soil should be well drained potting soil). They may be field planted after a year or two, depending in the size of your chosen tree tube. Always keep the tree watered during drought, and routinely check for insect predation and signs of fertilization needs.

UpS recommendations

  • Limit wild harvest to trees struck by natural disaster such as storms, otherwise use cultivated resources only
  • Possible substitutions include marsh mellow, comfrey, and mullein.

-Paul Strauss, Planting the Future, pg. 203-209


Slippery Elm Podcast -The Plant Detective by Flora Delaterre

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