Common Name: Marsh Andromeda

General Information

Andromeda polifolia is an evergreen shrub producing a loose clump of branching stems 5 - 80cm tall from a creeping rootstock[, ].
The plant has been used to make a tea, but some caution needs to be exercised. It is also used medicinally and as a source of tannins. It is often grown as an ornamental in gardens.

Known Hazards

All parts of the plant (including the leaves, flowers and pollen) contain greater or lesser amounts of the toxic compound andromedotoxin (also known as grayanotoxin). Rarely lethal to humans (and used medicinally in some herbal disciplines), this compound causes dose-dependant overstimulation of the central nervous system with symptoms including various cardiovascular effects (mainly low blood pressure and cardiac rhythm disorders); nausea and vomiting; and a change in consciousness. The effects commence shortly after ingestion and last around two days. These effects are also transferred to honey made from the nectar of the flowers. In some parts of the world bees are used to deliberately produce a honey rich in andromedotoxin which is then eaten for its supposed medicinal, hallucinogenic and aphrodisiac effects.
In contrast to humans, many other creatures are more susceptible to the toxin and it has sometimes proved lethal to grazing animals and household pets. Some forms of honeybees are also killed by the toxin (resistant forms of the bee are used for honey production). Bumblebees are not affected, however, and are also more efficient in pollinating rhododendron flowers, so one theory is that the toxin is produced by the plant in oder to favour the bumblebee and improve fertilization rates[].

Botanical References

, ,

Range

Northern temperate and Arctic regions, in Europe, including Britain, Asia and America

Habitat

Bogs, rarely on wet heaths, at altitudes up to 500 metres[]. Rare and decreasing in the south of Britain[]. Sphagnum peat bogs, acid swamps, margins of pools throughout boreal forest and arctic; at elevations to 1,500 metres[].

Properties

Edibility Rating
Medicinal Rating
Other Uses Rating
Habit	Evergreen Shrub
Height	0.30 m
Growth Rate	Slow
Pollinators	Bees, Lepidoptera, Self
Self-fertile	Yes
Cultivation Status	Ornamental, Wild

Cultivation Details

Requires a moisture-retentive, lime-free, humus- rich soil and a shady position[, , ]. The plant does not require acidic conditions; it reportedly can grow in soils with a pH range of 3.0 - 7.9. However, its ability to tolerate both the acid and high water levels allows it to thrive in bog systems[]. It is also able to grow in drier soils and can persist in drained bogs long after the sphagnum mosses have disappeared[].
Plants spread slowly by means of suckers when they are grown in a suitable position[].
A very ornamental plant, there are many named varieties[].

Edible Uses

The tender leaves and shoot-tips are boiled as an aromatic tea[, ]. A delicious drink[]. Some caution is advised since boiling the plant or infusing it in hot water is said to release a toxic chemical[]. It is safer to soak the leaves in a jar of water in direct sunlight to make 'sun tea'[].

Medicinal

The plant is used as a respiratory aid in the treatment of catarrh[]. Some caution is advised, see notes above on toxicity.

Other Uses

Tannin is obtained from the leaves and twigs[, ].

Propagation

Seed - sow late winter/early spring in an acid compost in the greenhouse. Surface sow or only just cover the seed and place in a lightly shaded position[, ]. The seed usually germinates in 1 - 2 months at 12°c[]. Prick out the young seedlings into individual pots as soon as possible, they are prone to damp-off and so should be kept well ventilated[]. Grow them on in the greenhouse for at least their first winter and plant them out in early summer once they are 15cm or more tall.
Cuttings of half-ripe wood, 5 - 7cm with a heel, mid summer in a frame in a shady position. Takes 15 months[].
Layering in August in a semi-shady position. Takes 18 months[].
Division in early spring. The plants should be 'dropped' beforehand[]. This entails digging up the plant 6 to 12 months earlier and replanting it somewhat more deeply. The buried branches will then root and form new plants when divided.