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Rhododendron groenlandicum
Will Clausen explores Labrador-tea, his special relationship with this hardy plant, and the good and bad aspects of drinking a brew.
Rhododendron groenlandicum
Labrador-tea
By Will Clausen, Chester B. Allen, Jr., Horticulture Fellow
Acidic bogs contain many remarkable and enduring plant species. It’s a tough place to live and it requires a certain type of plant that is capable of surviving on the fringe. One of my favorite acid-thriving plants is Rhododendron groenlandicum, commonly called Labrador-tea. This hardy shrub has a fragrant aroma and was formerly known as Ledum groenlandicum, as its outward appearance varies in some respects from other species of rhododendron.
Like other ericaceous plants, Labrador-tea has stiff leathery leaves which help to reduce transpiration and are able to survive throughout the winter. Despite the fact that these plants tend to grow in very wet habitats, water loss can still be an issue during certain times of the year. Labrador-tea has a few obvious distinguishing characteristics that make it easy to identify. The most striking is the mat of wooly hair that you find on the underside of the leaves. On old growth leaves the hair is rust colored, while new growth leaves are lighter. You also find hair growing on new stems. This hair plays an important role in slowing the release of water as the plants are unable to close their stomata when water availability is low.
The plant blooms in late spring with small white flowers growing in a terminal cluster. The flowers have five petals and long, spreading stamen. The resulting fruit is a small ovular capsule attached to a drooping pedicle. Likely due to the harsh growing conditions of its habitat, Labrador-tea is a prolific producer of seeds with as many as 50 viable seeds being produced by each flower. A very small amount of these wind-dispersed seeds find themselves in the correct growing environment and germinate.
Labrador-tea is a staple of low elevation bogs, although it can be found growing in poorly drained sub-alpine areas as well. Its North American range stretches from the Atlantic to the Pacific Oceans, throughout Canada, and northern sections of the United States. Fire plays an important role in creating the ideal habitat for Labrador-tea as it prefers full sun. Encroaching tree species such as tamarack (Larix laricina) and black spruce (Picea mariana) slowly shade out this shrubby plant in the absence of a regular disturbance regime. In fact, even human caused disturbances such as road construction, logging, and peat mining have a beneficial effect on Labrador-tea populations. I would never put this down as a reason to continue high impact activities in such a fragile ecosystem, but a fact is a fact. Following a low intensity disturbance, Labrador-tea is one of the first woody species to recolonize as it grows much more rapidly than large tree species.
Labrador-tea has a long cultural history with various Native American tribes, as well as early European colonists. Its leaves are commonly picked and dried to make tea, the source of its common name. The tea has a distinct earthy taste with very good flavor. However, be aware that you should only drink the tea in small quantities and at low concentrations because the leaves possess a compound called ledol, which can cause sickness when ingested in excess. Drinking the tea in normal amounts is totally safe, however, if you’re looking to go on a tea binge, try another blend.
Labrador-tea is also reported to have many medicinal benefits and has been used to attempt to cure ailments ranging in severity from stomach aches to leprosy. Native Americans have used it for its medicinal qualities for a very long time, and recently studies have shown that it does possess anti-inflammatory and antioxidant compounds.
I have a close personal history with Labrador-tea after spending a good deal of time one rainy southeast Alaskan summer taking samples of it from the muskegs that dot the landscape. I have very vivid memories of trying in vain to ignore the hoards of bloodthirsty insects swarming around me, of the endless cold rain, of regularly checking over my shoulder for marauding bears, and of dividing samples of Labrador-tea with numb fingers into new growth, old growth, and leaves to be weighed. It was tough love; one with memories that grow with time and distance. But this plant has stuck with me and I find it fascinating. I think that it’s important to have at least one plant in your life that has given you a hard time. Ours is a tough relationship, but that’s how it should be with such a tough plant.
Reference:
Cullina, W. 2002. Native Trees, Shrubs, and Vines: A guide to using, growing, and propagating North American woody plants. Houghton Mifflin Company; Boston.
http://www.fs.fed.us/database/feis/plants/shrub/ledgro/all.html
http://www.fs.fed.us/global/iitf/pdf/shrubs/Ledum%20groenlandicum.pdf
