Common Name:

General Information

Rhododendron campanulatum is an evergreen shrub that can grow from 1 - 4.5 metres tall[]. Some plants in cultivation in western Scotland have attained a height of more than 9 metres with a bole 40cm in diameter[].
The plant is harvested from the wild for local use as a medicine and source of materials. It is often grown as an ornamental.

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 order to favour the bumblebee and improve fertilization rates[].
The smoke from burned leaves is very acrid and irritant[].
The flowers can cause intoxication if eaten in large quantities[, ]. The nectar from the flowers can cause varying degrees of toxicity[].

Botanical References

, ,

Range

E. Asia - Himalaya regions of China (Xizang), northern India from Kashmir to Sikkim, Nepal, Bhutan

Habitat

Found on open slopes in the alpine zone; at elevations from 2,800 - 4,400 metres[]. Rhododendron thickets, forests, mountain slopes[].

Properties

Medicinal Rating
Other Uses Rating
Habit	Evergreen Shrub
Height	3.00 m
Growth Rate	Slow
Pollinators	Insects
Cultivation Status	Ornamental, Wild

Cultivation Details

Rhododendron campanulatum is native to higher elevations in the Himalayas, where it can be found at elevations up to 4,400 metres. A moderaely cold-tolerant plant, when fully dormant it can withstand temperatures down to about -25°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[].
Succeeds in most humus rich lime free soils except those of a dry arid nature or heavy or clayey[]. Prefers a peaty or well-drained sandy loam[]. Succeeds in sun or shade, the warmer the climate the more shade a plant requires[]. Requires a pH between 4.5 and 5.5[].
Succeeds in a woodland though, because of its surface-rooting habit[], it does not compete well with surface-rooting trees[]. Plants need to be kept well weeded, they dislike other plants growing over or into their root system, in particular they grow badly with ground cover plants, herbaceous plants and heathers[].
A moderate to slow-growing plant[].
There are many named varieties selected for their ornamental value[].
Plants form a root ball and are very tolerant of being transplanted, even when quite large, so long as the root ball is kept intact[].
Plants in this genus are notably susceptible to honey fungus[].

Edible Uses

None known

Medicinal

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

The leaves are mixed with tobacco and used as a snuff in the treatment of colds and headaches that affect only one side of the head[].
The juice of the leaves is used in the treatment of chronic rheumatism, sciatica and syphilis[, , ].

The dried twigs and wood are used in the treatment of phthisis and chronic fevers[].

The plant (part not specified) is said to have an anti-tubercular effect[].

Other Uses

The light pinkish-red wood is moderately hard[].
An excellent fuel wood is obtained from this plant[].

Propagation

Seed - best sown in a greenhouse as soon as it is ripe in the autumn and given artificial light. Alternatively sow the seed in a lightly shaded part of the warm greenhouse in late winter or in a cold greenhouse in mid spring. Surface-sow the seed and do not allow the compost to become dry[]. Pot up the seedlings when they are large enough to handle and grow on in a greenhouse for at least the first winter.
Layering in late July. Takes 15 - 24 months[].
Cuttings of half-ripe wood, August in a frame. Difficult[].