Common Name: Labrador Tea

General Information

Rhododendron groenlandicum is an evergreen shrub with erect and/or prostrate stems growing from a rhizomatous rootstock; it can grow 20 - 150cm tall[].
The plant is often used to make a tea and is often used medicinally. It is harvested from the wild for mainly local use as a food, medicine and source of materials. It is grown as an ornamental in gardens.

Known Hazards

Plants contain a narcotic toxin called Ledol - this is a sesquiterpene that can cause cramps, paralysis, and delirium. Ledol is also said to have various beneficial effects if consumed in the correct dosage and it is said that, when ingested as a herbal tea, it only causes problems if the leaves are cooked for a long period in a closed container[].

Botanical References

, ,

Range

Northern N. America - Alaska to Greenland and Newfoundland, south to Oregon, Idaho, Manitoba, Minnesota and Pennsylvania

Habitat

Bogs, spruce forests, muskeg, swamps, stream margins, talus slopes, tundra; at elevations up to 2,000 metres[]. Cold bogs and montane coniferous woods[, ].

Properties

Edibility Rating
Medicinal Rating
Other Uses Rating
Habit	Evergreen Shrub
Height	1.50 m
Pollinators	Bees
Cultivation Status	Ornamental, Wild

Cultivation Details

Rhododendron groenlandicum is hardy to at least -15°c[]. Although cold-tolerant when dormant, the flowers and young growth of Rhododendrons are very susceptible to damage by late frosts in regions where these are likely to occur after new growth has commenced in the spring[].
Requires a lime-free loam or peaty soil[, ]. Prefers a moist humus-rich acid soil in shade or semi-shade[]. Plants flower more freely when grown in a sunny position. Plants grow better if they have certain fungal associations in the soil. The best way of providing this is to incorporate some soil from around well-growing established plants into the soil for the new plant[].
The leaves and the flowers are very aromatic[, ].
Plants benefit from removing the dead flowers before they set seed[]. This prevents them putting too much energy into seed production at the expense of more flowers and leaves.
This species is considered by some botanists to be no more than a sub-species of Rhododendron tomentosum[, ].
A good bee plant[].

Edible Uses

Some caution is advised if consuming this plant - see the notes above on toxicity.

A fragrant and soothing tea is made from the leaves[, , , , ]. The spicy leaves make a very palatable and refreshing tea[]. The North American Indians would often flavour this tea with the roots of liquorice fern, Polypodium glycyrrhiza[]. When lemon is added they can be used as iced tea[]. The leaves were once added to beer in order to make it heady[].
Some caution is advised, see the notes above on toxicity. It would be better to brew the tea in cold water by leaving it in a sunny place, or to make sure that it is brewed for a short time only in an open container.

The leaves are used as a flavouring, they are a bayleaf substitute[].

Medicinal

Some caution is advised in the medicinal usage of this plant - see the notes above on toxicity.

Labrador tea was employed medicinally by several native North American Indian tribes who used it to treat a variety of complaints[]. In modern herbalism it is occasionally used externally to treat a range of skin problems.

The leaves are analgesic, blood purifier, diaphoretic, diuretic, pectoral and tonic[, , , ]. A tea is taken internally in the treatment of headaches, asthma, colds, stomach aches, kidney ailments etc[, ].
Externally, it is used as a wash for burns, ulcers, itches, chapped skin, stings, dandruff etc[, , ]. An ointment made from the powdered leaves or roots has been used to treat ulcers, cracked nipples, burns and scalds[].

An essential oil obtained from the plant is used in aromatherapy[].

The plant is apparently a mild narcotic, it was taken by Indian women three times daily shortly before giving birth[]

Studies have shown that a methanol extract of the leaves and twigs has significant anti-inflammatory and antioxidant activities[].
A water extract (tea) of the twigs has been shown to be active against lung and colon carcinoma cell lines[].

Other Uses

The leaves are hung up in the clothes cupboard in order to repel insects[]. The branches are also placed among grain in order to keep mice away[]. A strong decoction of the leaves, or a tincture, is used to kill lice, mosquitoes, fleas and other insects[, , ].

The leaves contain tannin[].

A brown dye is obtained from the plant[].

Propagation

Seed - surface sow in a shady part of the greenhouse in late winter or early spring[, ]. Another report says that the seed is best sown in the autumn as soon as it is ripe[]. Germination is variable and can be quite slow. Prick out the seedlings into individual pots as soon as they are large enough to handle and grow the pots on in a shady frame for 18 months before planting them out into their permanent positions[].
Cuttings of half-ripe wood, 5 - 8cm with a heel, mid summer in a frame. Plant out in spring. Fair percentage[].
Cuttings of mature wood, late autumn in a frame[].
Layering in the autumn. Takes 12 months[].
Division.