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Labrador tea

Labrador tea (Rhododendron groenlandicum, formerly Ledum groenlandicum) is an evergreen shrub in the heath family (Ericaceae), typically growing 0.2 to 1.5 meters tall from a rhizomatous rootstock, with aromatic, oblong leaves (2–5 cm long) that are dark green and leathery above and rusty-hairy beneath, and clusters of small white flowers blooming in spring to early summer.^[1]^[2]^[3] Native to northern regions of North America, including Alaska, Canada, and Greenland, as well as parts of the northeastern and Pacific Northwest United States, it thrives in acidic, moist environments such as bogs, fens, muskegs, tundra, and peaty wetlands at elevations up to 2,800 meters.^[1]^[2]^[4] Ecologically, Labrador tea plays a role in wetland ecosystems by providing nectar for pollinators like butterflies and serving as browse for wildlife such as caribou and moose, while its clonal reproduction via layering contributes to stable cover in harsh, northern habitats.^[1]^[2] Traditionally harvested by Indigenous peoples, including tribes like the Quinault, Makah, Ojibwa, and Bella Coola, the leaves have been used to brew a fragrant tea substitute, often flavored with other plants, and added to beer for flavor and potency.^[1]^[4]^[3] Medicinally, infusions of the leaves and flowering shoots have been employed as a tonic for ailments including colds, sore throats, coughs, rheumatism, asthma, stomach issues, and lung infections, with documented anti-inflammatory, antioxidant, and antimicrobial properties.^[5]^[1]^[4] However, the plant contains potentially toxic sesquiterpenes that can cause nausea, delirium, or more severe effects in large doses, making it unsafe for concentrated use, during pregnancy, or without proper preparation.^[5]^[3] Beyond human uses, it repels insects and yields tannins and dyes, though overharvesting and habitat loss pose conservation concerns in southern ranges like New Jersey, where it is listed as endangered.^[3]^[2]

Taxonomy and Nomenclature

Classification

Labrador tea is classified within the kingdom Plantae, phylum Tracheophyta, class Magnoliopsida, order Ericales, family Ericaceae, genus Rhododendron, subgenus Rhododendron, section Rhododendron, and subsection Ledum.^[6] The plants comprising Labrador tea were historically recognized as the genus Ledum, established in the 18th century, but cladistic analyses based on morphology in the 1990s proposed their integration into Rhododendron as section or subsection Ledum. Subsequent molecular phylogenetic studies in the early 2000s, using sequences from genes such as RPB2 and chloroplast markers, provided robust evidence supporting this reclassification by demonstrating that Ledum species are nested within Rhododendron clades, sharing a common ancestry with other rhododendrons.^[7] Members of the Ericaceae family, to which Labrador tea belongs, are predominantly shrubs or small trees adapted to acidic, nutrient-poor soils, where they often form ericoid mycorrhizal associations with fungi to enhance nutrient uptake, particularly of nitrogen and phosphorus from organic matter.^[8] These adaptations enable Labrador tea species to thrive in challenging environments like bogs and peatlands. The subsection Ledum includes three main species, with further details on their distinctions provided in the species and variations section. The common name "Labrador tea" derives from its traditional use as a tea substitute by Indigenous peoples in the Labrador region of Canada; the specific epithets reflect geographic origins (groenlandicum for Greenland) or morphological traits like tomentose indumentum (tomentosum).

Species and Variations

Labrador tea encompasses three primary species within the Rhododendron subsection Ledum: Rhododendron groenlandicum, R. tomentosum, and R. columbianum (synonym R. neoglandulosum in some older frameworks). These evergreen shrubs are distinguished by variations in leaf indumentum, aroma intensity, and geographic distribution, reflecting adaptations to boreal and subarctic environments.^[9]^[10] Rhododendron groenlandicum, the bog Labrador tea, is the most widespread North American species, native to eastern and western regions including Greenland, Canada, and the northern United States. It features non-glandular, dense ferruginous (rusty) hairs on the leaf undersides that obscure the underlying glandular scales, contributing to its relatively lower toxicity compared to congeners. This species exhibits a mild conifer-like aroma when leaves are crushed and thrives in acidic bogs and wetlands.^[11]^[12]^[10] In contrast, R. tomentosum, the northern Labrador tea, predominates in Eurasian peatlands and extends into northern North America. Its leaves bear sticky glandular hairs and prominent glandular-peltate scales, resulting in a stronger, more pungent aroma due to higher concentrations of volatile compounds like ledol. This species often displays prostrate growth and narrower, linear leaves, adapting to subarctic tundra and muskeg habitats.^[13]^[12]^[10] R. columbianum, known as western Labrador tea (syn. R. neoglandulosum), is confined to western North America, from British Columbia to California and eastward to the Rockies. It shows intermediate traits, with glandular hairs and visible shining resin glands on petiolate leaves, alongside elevated essential oil content that enhances its aromatic profile. This species grows taller than its relatives, reaching up to 2 meters, and occupies subalpine meadows and acidic bogs.^[14]^[10] Intraspecific variations occur within these species, such as in R. tomentosum, where subspecies like R. tomentosum subsp. decumbens exhibit more decumbent stems in coastal regions. For R. groenlandicum, eastern populations (subsp. groenlandicum) differ subtly from western ones in leaf width and hair density, though no formal subspecies are universally recognized. Hybridization happens in zones of overlap, particularly between R. groenlandicum and R. columbianum in the Pacific Northwest, producing intermediates with mixed glandular and non-glandular traits.^[13]^[11]^[15]

Botanical Description

Morphology

Labrador tea, or Rhododendron groenlandicum, is a low-growing, evergreen shrub typically reaching heights of 0.2 to 1.5 meters, though it often remains under 1 meter tall, with a slow growth rate that contributes to its compact, bushy habit.^[2]^[16] The plant exhibits a rhizomatous growth form, producing multiple upright or prostrate branches that spread to form dense colonies.^[17] Its overall structure is adapted for persistence in challenging environments, with woody stems that are reddish-brown to gray, initially covered in dense, woolly hairs that become smoother with age, and bark that is thin, smooth, and prone to peeling.^[18]^[2] The root system consists of shallow, fibrous roots that form extensive mats, often in association with ericoid mycorrhizae, enabling effective colonization of peat substrates.^[16] The leaves are alternate, simple, and leathery, measuring 2 to 6 cm in length and 0.5 to 2.5 cm in width, with an oblong to narrowly elliptic shape.^[19]^[20] The upper surface is dark green and smooth to sparsely hairy, while the margins are strongly revolute, and the underside is densely covered in rusty-brown to coppery woolly hairs, providing a distinctive indumentum that persists through the leaf's lifespan of about two years.^[17]^[2] These evergreen leaves remain functional into their second year before shedding in autumn, contributing to the plant's year-round foliage density.^[17] Flowers are small, approximately 8 to 10 mm in diameter, and arranged in terminal, umbellate clusters of 10 to 35 blooms, creating a rounded inflorescence at branch tips.^[17]^[2] Each flower features a funnel-shaped corolla with five white, oval petals and 5 to 10 exserted stamens, borne on pedicels 1.2 to 2.5 cm long; the calyx is short and five-parted.^[18]^[19] This floral morphology enhances the plant's visual appeal during its May to June blooming period.^[17]

Reproduction and Growth

Labrador tea (Rhododendron groenlandicum) typically flowers from late May to early June, producing clusters of small, white, bisexual flowers that are 8–10 mm in diameter and feature 5–10 stamens.^[21] These blooms occur at the ends of branches in umbel-like terminal clusters, with flowering times varying slightly by region, such as extending to mid-July in northern areas like Alaska.^[16] Pollination is primarily achieved through insects, including bees (Bombus and Apis species), butterflies, flies, and other hymenopterans, though the plant is self-compatible, allowing for self-pollination while cross-pollination predominates for optimal seed set.^[21]^[16]^[2] Following pollination, the plant develops dry, oblong-elliptic capsules measuring 5–7 mm long, which split into five valves and persist through winter to release seeds.^[21]^[2] Each capsule contains numerous tiny seeds, averaging over 50 to 133 per fruit, with a mean mass of about 0.0057 mg and slight wings that facilitate wind dispersal, though water can also aid spread in boggy habitats.^[21]^[16]^[2] Seeds germinate slowly under moist conditions, with fresh seeds achieving up to 58% germination rates, though viability declines rapidly with age; optimal germination requires light exposure, warm diurnal temperatures (around 16°C day/5°C night), and a pH range of 3.5–7.5.^[21]^[2] As a perennial evergreen shrub, Labrador tea exhibits a slow growth cycle, with shoot elongation primarily occurring from early June to early August and new leaves emerging annually while older leaves persist for about two years before shedding in autumn.^[21]^[2] It spreads clonally through rhizomes and layering, where branches root upon contact with moist substrates like moss, enabling vegetative propagation and resprouting from root crowns after disturbances.^[21]^[16]^[2] Seedlings grow slowly, often reaching only 4 mm in height over four months during the juvenile phase, with full maturity taking several years; the plant is long-lived, with individuals potentially surviving for decades in stable habitats.^[21]^[16] Seed germination is triggered by environmental cues such as cold stratification or exposure to winter temperatures, which break any potential dormancy and enhance viability, particularly in moist, acidic peatlands with pH around 5.5.^[21]^[16] Vegetative growth and clonal expansion are stimulated by high light availability, such as from canopy gaps or post-fire conditions, while overall reproduction responds to seasonal changes in temperature and moisture.^[21]^[2] Propagation via cuttings is feasible under controlled conditions, mimicking natural layering in greenhouse settings with acidic soils.^[16]

Habitat and Ecology

Distribution

Labrador tea species exhibit a nearly circumboreal distribution across the northern hemisphere, primarily in cool temperate and subarctic regions, with disjunct populations occurring in high latitudes such as Greenland and isolated southern outposts in North America.^[22] Rhododendron groenlandicum, commonly known as bog Labrador tea, has a widespread range throughout northern North America, extending from Alaska eastward to Newfoundland and Labrador, and southward to the northern fringes of the contiguous United States, including states like Minnesota, Maine, and Pennsylvania.^[23]^[16] This species is absent from southern latitudes and warmer regions, with its southern populations often disjunct and rare, such as in isolated bogs in the northeastern U.S.^[24] Rhododendron tomentosum, or marsh Labrador tea, is primarily distributed across Eurasia, ranging from Scandinavia and Iceland through central and northern Europe, Russia, Siberia, and into eastern Asia, including Japan, Korea, and parts of China and Mongolia.^[25] It also occurs natively in northern North America, including Greenland, Alaska, and parts of Canada.^[25] Rhododendron neoglandulosum, known as western Labrador tea, is endemic to western North America, distributed from British Columbia southward to California and eastward to Montana and Colorado, favoring coastal and montane areas.^[26] The current distributions of Labrador tea species reflect post-glacial expansions following the retreat of ice sheets approximately 10,000–12,000 years ago, which allowed migration northward and into newly exposed habitats across the circumboreal zone.^[22] Southern edge populations, particularly of R. groenlandicum, face threats from ongoing climate shifts, leading to contractions in range at lower latitudes.^[16]

Environmental Preferences and Role

Labrador tea (Rhododendron groenlandicum) thrives in wetland environments characterized by high moisture and acidity, including peat bogs, fens, swamps, and other acidic wetlands. These habitats typically feature poorly drained, organic-rich soils with a pH ranging from 3.5 to 5.5, where the plant associates closely with sphagnum moss and other ericaceous species such as leatherleaf (Chamaedaphne calyculata). It exhibits strong tolerance to cold temperatures, surviving down to -40°C in USDA hardiness zone 2, and prefers conditions with low nutrient availability and minimal subsurface water flow.^[16]^[2]^[27] In its ecosystems, Labrador tea plays a key role in stabilizing peat soils through its extensive root mats, which extend up to 45 cm deep and help prevent erosion in waterlogged environments. It serves as an important nectar source for pollinators, particularly bumblebees (Bombus spp.) and other bees, supporting insect-mediated reproduction during its flowering period. The plant also provides browse and cover for wildlife, including moose (Alces alces), white-tailed deer (Odocoileus virginianus), snowshoe hares (Lepus americanus), and various birds, though its leaves' alkaloids reduce palatability for heavy grazing. As a characteristic species of intact boreal peatlands, it acts as an indicator of bog health, signaling stable acidic and hydric conditions.^[16]^[16]^[16] Symbiotically, Labrador tea forms ericoid mycorrhizal associations with fungi that enhance nutrient uptake, particularly nitrogen and phosphorus, in the low-nutrient soils of its habitats. It exhibits allelopathic effects, releasing compounds that inhibit the growth of competing vegetation, such as grasses like bluejoint reedgrass (Calamagrostis canadensis), thereby maintaining dominance in shrub layers.^[16]^[28] Adapted to cool, humid climates with high precipitation (up to 98 inches annually in some regions), Labrador tea is vulnerable to climate change impacts like increased drying and warming trends, which could alter peatland hydrology and reduce suitable habitat at the southern edges of its range.^[16]^[2]^[29]

Traditional and Modern Uses

Medicinal Uses

Indigenous peoples across North America have long utilized Labrador tea (Rhododendron groenlandicum) for its therapeutic properties, particularly in treating respiratory ailments and other common conditions. The Inuit of Nunavik traditionally boiled the leaves or chewed them to address breathing problems, stop bleeding, strengthen the body, and alleviate general aches and pains, often preparing an ointment with seal oil for fevers and sore throats. Similarly, the Cree and Métis of Canada employed infusions or chewed leaves to manage stomach flu, diarrhea, chills, pneumonia, and urinary difficulties, while the Ojibwa used the leaves to treat ulcers. Groups like the Denyaavee (an Athabascan people related to the Dene) prepared leaf tea for upset stomachs, heartburn, and arthritis, with flower tea used for colds and the cooled infusion as a gargle for sore throats or a wash for skin issues. The Pomo and related tribes in Northern California boiled the leaves to create a medicinal tea for coughs and colds, often applying poultices for wounds and using it as a diuretic for kidney problems and rheumatism. The plant's medicinal efficacy stems from its essential oils and phenolic compounds, which exhibit anti-inflammatory, expectorant, and antimicrobial effects. These properties facilitate respiratory relief, such as loosening mucus and reducing inflammation in the lungs and throat, making it suitable for steam inhalations to ease congestion from colds or fevers. Studies have identified ledol and other terpenoids in the essential oils as contributors to these antimicrobial actions, while flavonoids provide antioxidant support to combat oxidative stress associated with inflammation. Modern research since 2010 has substantiated some traditional applications, revealing strong antioxidant activity in leaf extracts that may support immune function through free radical scavenging. Antifungal properties have been demonstrated in essential oils, effective against pathogens like Candida albicans, suggesting potential in herbal supplements for infection prevention. Limited preclinical studies indicate benefits for sore throat relief via anti-inflammatory mechanisms, though human clinical trials remain scarce; one investigation highlighted its incorporation into immune-supporting formulations for respiratory health. Additionally, antidiabetic effects have been noted in animal models, with extracts improving renal integrity in obese mice, pointing to broader metabolic applications. A 2023 study identified compounds in the leaves with activity against malaria parasites, while a 2024 analysis of methanolic extracts confirmed strong antioxidant, anti-inflammatory, and anticancer properties.^[30]^[10] Preparation methods draw from ethnobotanical records to ensure safety and efficacy, emphasizing moderation due to potential toxicity from compounds like ledol. A typical infusion uses 1-2 dried leaves (or about 1 teaspoon) per cup of boiling water, steeped for 5-10 minutes, with consumption limited to one cup daily to avoid adverse effects. For poultices or washes, leaves are simmered longer and applied topically after cooling.

Culinary and Other Applications

Labrador tea leaves have been traditionally brewed into an herbal beverage by northern indigenous peoples, including tribes such as the Quinault, Makah, Chippewa, Menominee, Potawatomi, Micmac, Maliseet, Penobscot, and Passamaquoddy, who valued its fragrant, refreshing qualities.^[1] The preparation typically involves boiling a handful of fresh or dried leaves in a quart of water for 15 to 20 minutes, often sweetened with maple sugar or honey to create a mild, aromatic drink enjoyed warm.^[1]^[31] This practice persists among some Native American families and was adopted by European colonists in the 18th century as a substitute for imported tea during shortages.^[1] In culinary applications, dried Labrador tea leaves serve as a spice to flavor meat rubs, stews, soups, sauces, and salads, imparting a distinctive woody, resinous note.^[31] In Quebec cuisine, the leaves are particularly used as a marinade for game meats like deer or moose, enhancing dishes with their strong aromatic profile reminiscent of mint and fir.^[31]^[32] Historically, in 18th-century Europe and among American colonists, the leaves were added to beer as part of gruit mixtures before hops became dominant, contributing a bitter, spicy character noted for its flavoring effects.^[31] Beyond food and drink, Labrador tea's essential oil, characterized by a woody, camphor-like scent derived from compounds such as ledol and palustrol, finds use in perfumes and soaps for its coniferous aroma.^[31] Traditionally, the plant has served as a natural insecticide; fresh leaves are crushed and macerated in oil, such as canola or olive, for two weeks to create a repellent applied to skin or used in storage to deter mosquitoes and fleas.^[31]^[33] In modern products, the oil appears in skincare formulations for its aromatic qualities.^[31] Culturally, Labrador tea holds significance in First Nations traditions, symbolizing resilience in the Labrador region where it thrives, and is incorporated into rituals for purification.^[1] Among Athabaskan peoples, a stalk is thrown out the door during ceremonies to dispel illness or negative spirits from a household.^[34] In Métis sweat lodge practices, leaves are splashed on hot rocks to release an aromatic vapor, enhancing the ceremonial atmosphere.^[35]^[33]

Toxicology

Chemical Constituents

Labrador tea, primarily referring to Rhododendron groenlandicum and related species in subsection Ledum, contains a variety of bioactive compounds, including essential oils, terpenoids, flavonoids, and tannins. The essential oils constitute 0.3–2.5% of the leaf dry weight in R. groenlandicum, comprising mainly sesquiterpenes and monoterpenes such as ledol, palustrol, sabinene, limonene, p-cymene, and α-pinene.^[36] These oils contribute to the plant's characteristic aromatic profile and are extracted via steam distillation, a method that isolates the volatile components effectively.^[36] Among the primary toxins are grayanotoxins, a group of neurotoxic diterpenoids present in varying amounts across species, with R. groenlandicum exhibiting the lowest levels compared to other rhododendrons.^[10] Another key toxin is ledol, a sesquiterpene alcohol responsible for potential narcotic effects, with concentrations varying significantly by species; it is highest in R. tomentosum (up to 30.5% of essential oil in some populations) and notably lower or absent in certain R. groenlandicum samples.^[36]^[10] Beneficial compounds include flavonoids such as quercetin and hyperoside, which act as antioxidants, along with arbutin, a phenolic glycoside noted for its urinary antiseptic properties, and tannins comprising 8–17% of the leaf material.^[36] These non-volatile constituents are more abundant in the leaves and contribute to the plant's traditional medicinal applications, though their extraction is less targeted than that of essential oils.^[36] Species variations influence the chemical profile: R. groenlandicum has lower grayanotoxin and ledol levels but higher proportions of sabinene (up to 11.9%) and α-selinene (19.8%), enhancing its milder aroma; in contrast, R. neoglandulosum shows elevated ledol content, contributing to a stronger scent, while R. tomentosum is dominated by ledol and palustrol (15.9–53.5%).^[10] Essential oil concentrations peak in spring leaves, reaching approximately three times higher than in older foliage, due to heightened terpenoid biosynthesis during early growth.^[36]

Health Risks and Safety Guidelines

Labrador tea (Rhododendron groenlandicum), containing grayanotoxins, can cause acute toxicity in humans when consumed in excessive amounts, leading to symptoms including nausea, vomiting, and dizziness.^[37] In rare severe cases, higher doses may result in convulsions, paralysis, and respiratory failure due to the neurotoxic effects of these compounds.^[38] Such intoxications are uncommon in humans but have been documented in case reports involving herbal teas or concentrated preparations.^[39] Chronic exposure from overuse may lead to adverse effects as suggested by traditional herbal cautions.^[5] It is contraindicated during pregnancy, as it may stimulate uterine contractions and cause miscarriage, and should be avoided in individuals with epilepsy due to risks of seizure exacerbation from grayanotoxin-induced neurological disturbances.^[40] Additionally, caution is advised for those taking heart medications, given interactions with CYP3A4-metabolized drugs like certain antihypertensives or antiarrhythmics, potentially altering their efficacy or increasing toxicity.^[40] To minimize risks, consumption should be limited to one cup of tea daily, prepared by steeping no more than one teaspoon (approximately 5 mL) of dried leaves in 250 mL of boiling water for 3–10 minutes, and raw leaves should be avoided entirely due to higher toxin concentrations.^[37] R. groenlandicum is preferred over other species like R. tomentosum for its lower grayanotoxin levels, and medicinal use requires consultation with a healthcare professional to assess individual risks.^[10] Documented poisonings in livestock, particularly sheep, highlight the plant's toxicity, with cases of gastrointestinal distress, cardiac arrhythmias, and death reported from grazing on foliage containing 0.2% body weight equivalents.^[38] Labrador tea is not approved by the FDA for safety or efficacy in treating any condition, and its historical use as a beer adjunct was banned in certain regions, such as medieval Norway around 1100 CE, due to intoxicating and toxic effects from ledol and grayanotoxins.^[37]^[41]

Harvesting and Conservation

Collection Practices

Labrador tea (Rhododendron groenlandicum) leaves are typically harvested in spring, prior to flowering (April-May), or in fall (September-October), as these periods align with optimal leaf quality for traditional uses.^[1] Harvesting during the flowering period should be avoided to minimize stress on the plant.^[1] Due to its slow growth rate, collectors must limit harvests to ensure plant recovery.^[42] Sustainable techniques emphasize selective hand-picking to preserve plant health, such as removing only the previous year's old leaves and leaving at least several current-year leaves on each stem.^[43] Ideally, harvest no more than one leaf per stem every other year, using clean, sharp shears or scissors for precise cuts that minimize damage to the stem.^[44] Target the edges of plant stands rather than the core to protect denser populations, and select only from healthy, well-established individuals while avoiding plants near roadsides or polluted areas to prevent contamination.^[44] Experimental studies confirm that harvesting all leaves leads to significant mortality (up to 66.7% after two consecutive full harvests), underscoring the need for these restrained methods.^[45] Post-harvest, leaves should be cleaned by rinsing under cold water and inspected to remove any molded or spoiled ones.^[1] Air-drying in a shaded, well-ventilated area for 1-2 weeks, or using low-heat oven drying, preserves essential oils; hang small bundles or spread on racks until brittle.^[44] Store dried leaves in airtight, clean containers in a dry location to maintain potency for up to a year.^[44] Avoid plastic during initial drying to prevent moisture buildup and spoilage.^[1] Legal considerations include obtaining permits for harvesting in protected areas such as national parks, and always securing permission on private lands.^[44] Harvesters must respect indigenous rights, particularly in regions where communities like the Ojibwa have traditional harvesting practices.^[1] In some areas, adherence to codes of ethics or certifications, such as those from wild harvesters' associations, is required to ensure ethical sourcing.^[46]

Sustainability Considerations

Labrador tea (Rhododendron groenlandicum) faces several conservation challenges, primarily related to habitat degradation and human activities. Major threats include habitat loss from peat mining and drainage, which destroy or alter the acidic, wet bog environments essential for the species.^[47]^[48] Climate change exacerbates these issues through warming temperatures, earlier snowmelt, and declining soil moisture, leading to drying bogs that reduce suitable habitat, particularly at the southern edges of its range.^[49]^[48] Overharvesting poses an additional risk, as the slow-growing shrub can be weakened by excessive leaf removal, limiting its recovery and reproductive capacity.^[43]^[50] Globally, Labrador tea is considered secure (G5 rank), reflecting its wide circumboreal distribution, but it is locally rare and vulnerable in southern ranges due to restricted populations and ongoing declines.^[48] In the United States, it is presumed extirpated in Ohio (as of 2023),^[51] special concern in Connecticut,^[52] and rare in Pennsylvania,^[20] with protections under state endangered species laws in these areas. Similar local protections exist in some Canadian provinces, where it is monitored for rarity in southern boreal zones.^[16] Conservation strategies emphasize sustainable management to protect wild populations. Promoting cultivation in nurseries using sphagnum or peat moss substrates has shown promise for revegetation of disturbed sites, reducing pressure on natural stands.^[53]^[54] Education on sustainable harvesting quotas, such as leaving current-year leaves on plants to ensure recovery, helps prevent overexploitation.^[43]^[46] Monitoring through citizen science platforms like iNaturalist supports population tracking, while bog restoration via rewetting drained peatlands aids habitat recovery.^[55]^[56] Recent developments in the 2020s include research on climate resilience, such as modeling habitat suitability for Labrador tea under warming scenarios to predict shrub expansion or contraction in tundra ecosystems.^[57] Indigenous-led stewardship programs in Arctic and subarctic regions integrate traditional knowledge for protecting and managing Labrador tea populations, emphasizing cultural and ecological sustainability.^[49]^[58]

References

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[28]
Labrador tea Rhododendron groenlandicum from New England ...
Labrador tea (Ledum groenlandicum) ; Height: 12-30 in ; Spread: 12-24 in ; Hardiness Zone: 2-6.Missing: cold | Show results with:cold
[29]
bio-intrusion barrier made of plants with allelopathic effects to ...
as a bio-intrusion barrier against incompatible plants. Bluejoint reedgrass, sheep laurel and bog Labrador tea are species that have been ...
[30]
[PDF] Identifying species in Pennsylvania potentially vulnerable to climate ...
Rhododendron groenlandicum (Labrador- tea). Southern edge of ... localized hydrological regime that may experience some drying due to climate change, its.
[31]
Labrador tea - the aromatic beverage and spice: A review of origin ...
Aug 7, 2025 · It is often sweetened or enriched with other flavors. Additionally, Labrador tea dried leaves are used to spice meat, soups, sauces, salads, ...Missing: culinary | Show results with:culinary
[32]
Regional Flavours: Labrador Tea - Québec maritime
Sep 22, 2017 · Storage and use. Labrador tea has a strong flavour and is very aromatic. It is therefore a good marinade for game meat. It can also be used ...<|separator|>
[33]
Labrador tea - Wapusk National Park
Feb 27, 2024 · An interesting practical use of Labrador Tea is to repel insects. The recipe is to crush fresh leaves, place them in a glass jar and cover them ...Missing: storage | Show results with:storage
[34]
Alaska's Wilderness Medicines - Labrador Tea
Other uses: There are ceremonial uses for Labrador tea; one is to turn a stalk and throw it out the door if a child is ill or if you want to get rid of ghosts.
[35]
None
### Summary of Labrador Tea Use in Sweat Lodge Ceremonies or Other Rituals
[36]
Labrador tea – the aromatic beverage and spice: a review of origin ...
Aug 25, 2014 · 15. Apart from the essential oil, Labrador tea contains also flavonoids (quercetin, hyperoside, arbutin), phenolic acids and tannins.
[37]
Labrador Tea Uses, Benefits & Dosage - Drugs.com
Jun 23, 2025 · Labrador tea has been used in folk medicine for cough, chest and kidney conditions, headache, rheumatism, diarrhea, sore throat, female disorders, and ...
[38]
Grayanotoxin Poisoning: 'Mad Honey Disease' and Beyond - PMC
Grayanotoxin poisoning, often from 'mad honey', causes dizziness, hypotension, and atrial-ventricular block. It's caused by grayanotoxins from plants, and can ...
[39]
Risks for human health related to the presence of grayanotoxins in ...
These may lead to complete atrioventricular block, convulsions, mental confusion, agitation, syncope and respiratory depression. For acute effects, the CONTAM ...
[40]
Bog Labrador Tea - Uses, Side Effects, and More - WebMD
People use bog Labrador tea for sore throat, chest congestion, coughs, lung infections, diarrhea, joint and muscle pain (rheumatism), and many other conditionsMissing: Inuit | Show results with:Inuit
[41]
Labrador tea--the aromatic beverage and spice: a review of origin ...
Additionally, Labrador tea dried leaves are used to spice meat, soups, sauces, salads, beer, cakes and other dishes. In agriculture, its insecticidal properties ...Missing: culinary | Show results with:culinary
[42]
Labrador Tea - PEI Untamed
Nov 13, 2024 · Labrador Tea has been used internally as a diuretic and for treatment of colds, sore throats, headaches, and diarrhoea, as well as externally to ...Missing: indigenous | Show results with:indigenous
[43]
Labrador tea: a treasure to be protected | Blog | Space for life
Jul 30, 2025 · It concludes that Labrador tea plants will die if all their leaves are removed. If only the previous year's leaves are picked, however, the ...
[44]
Foraging for Labrador Tea in Northwest Ontario - myBackyard,ca
Only pick leaves from healthy, well-established plants. · Avoid harvesting leaves from plants growing near roadsides or polluted areas, as they may have absorbed ...
[45]
(PDF) Impacts of experimental leaf harvesting on a North American ...
Aug 9, 2025 · In this exploratory study, we investigated the impact of leaf harvesting on Rhododendron groenlandicum (Oeder) Kron & Judd, a North American ...<|control11|><|separator|>
[46]
[PDF] LABRADOR TEA
Practice sustainable harvesting, by not over harvesting in one area. HARVESTER CERTIFICATION: • NFDC is working on providing organic certification on selective ...Missing: methods | Show results with:methods
[47]
Oil sands mining and reclamation cause massive loss of peatland ...
Mar 12, 2012 · Contrary to claims made in the media, peatland destroyed by open-pit mining will not be restored. Current plans dictate its replacement with ...
[48]
[PDF] Species: Labrador-tea (Rhododendron groenlandicum)
Labrador-tea is widely distributed in the more northern and cooler portions of North. America. It occurs locally in northern, mostly northeastern, Pennsylvania ...Missing: circumboreal | Show results with:circumboreal<|control11|><|separator|>
[49]
[PDF] Labrador Tea | qʷəlut - Tulalip Tribes Natural Resources
Below, we describe key findings from available studies predicting future changes in Labrador tea distribution within the geography of the Treaty of Point ...Missing: post- glacial expansion<|control11|><|separator|>
[50]
Red Lake Nation holds first indigenous food summit | MPR News
Sep 19, 2016 · Labrador tea is a slow-growing wetland shrub. Overharvesting the leaves from individual plants can prohibit sustainable growth. Monika ...
[51]
Bog Labrador Tea - Nature's Notebook - National Phenology Network
For Rhododendron groenlandicum, the fruit is a capsule that changes from green to brown and splits open to expose the seeds. Do not include empty capsules that ...Missing: pollination cycle
[52]
Labrador Tea History - Mother Earth Living
Feb 1, 1997 · Herbal tea has long been associated with rebellion in America. Hippies, beatniks, and jazz musicians all steeped their movements in herbed beverages.<|separator|>
[53]
[PDF] 26. Labrador Tea, Ledum palustre sensu lato (Rhododendron ...
North American Ledum includes three main taxa: L. palustre L. ssp. groenlandicum (Oeder) Hultén (L. groen- landicum Oeder, R. groenlandicum (Oeder) Kron & Judd).
[54]
Bog Labrador Tea (Rhododendron groenlandicum) - iNaturalist
Rhododendron groenlandicum (bog Labrador tea, formerly Ledum groenlandicum or Ledum latifolium), is a flowering shrub with white flowers and evergreen ...
[55]
[PDF] Playbook for Minnesota Peatlands - The Nature Conservancy
The Nature Conservancy proposes a three-pronged peatland strategy: protect large standing carbon stocks, re-wet partially drained peatlands in the north, and ...<|separator|>
[56]
Tundra shrub expansion in a warming climate and the influence of ...
Oct 12, 2022 · We modeled the effects of warming on habitat suitability in green alder, dwarf birch, Labrador tea, bog bilberry, and lingonberry and assessed ...
[57]
Protecting boreal plant species is a critical part of reconciliation efforts
Aug 10, 2023 · Plants with great nutritional and medicinal value like Labrador Tea are sprayed so that they do not compete with monocropping reforestation ...<|control11|><|separator|>