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Ericaceae FAMILY

Rhododendron hodgsonii

Rhododendron hodgsonii

Edibility
0/5
Medicinal
0/5

Safety & Hazards

Although no specific mention of toxicity has been seen for this species, all parts of Rhododendron species (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[1].

Cultivation Details

HabitEvergreen Tree
GrowthSlow

Rhododendron hodgsonii is not a very cold-tolerant plant, when fully dormant it can withstand short periods with temperatures down to about -10°c Although somewhat 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[2]. Rhododendron species generally succeed when grown in a non-compacted, humus rich lime free soil and a position with some shade, preferably light woodland shade. They strongly dislike soils of a dry arid nature, heavy soils or clays[3]. Prefers a peaty or well-drained sandy loam[3]. Succeeds in sun or shade, the warmer the climate the more shade a plant requires[2]. Requires a pH between 4.5 and 5.5[2]. Rhododendron species are mainly woodland species that grow well in the dappled shade and shelter given by the other woodland plants. They are surface-rooting species with a fibrous root system, however, and do not grow well close to trees that are also surface-rooting, nor do they do well with ground cover or other small plants growing over or into their roots[2, 4]. 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[2]. With its large rich green leaves and its beautiful bark, this species is one of the noblest of ornamental rhododendrons[5]. A very slow-growing tree[6].

Propagation

Seed - surface sow in a shady part of the greenhouse in late winter or early spring[7, 8]. Another report says that the seed is best sown in the autumn as soon as it is ripe[9]. 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[7]. Cuttings of half-ripe wood, 5 - 8cm with a heel, mid summer in a frame. Plant out in spring. Fair percentage[7]. Cuttings of mature wood, late autumn in a frame[8]. Layering in the autumn. Takes 12 months[7]. Division. Cite as: Temperate Plants Database, Ken Fern. temperate.theferns.info. 2026-02-21. <temperate.theferns.info/plant/Rhododendron+hodgsonii>

Pollinators

Data unavailable

References

  1. [1]Grayanotoxin Poisoning: ‘Mad Honey Disease’ and Beyond — Jansen S.A. et al · 2012 · https://doi.org/10.1007/s12012-012-9162-2 ↩︎An in-depth review of the literature on the toxic effects of a toxin widely found in the family Ericaceae
  2. [2]The New RHS Dictionary of Gardening. 1992. — Huxley. A. · MacMillan Press · 1992 · ISBN 0-333-47494-5 ↩︎Excellent and very comprehensive, though it contains a number of silly mistakes. Readable yet also very detailed.
  3. [3]RHS Dictionary of Plants plus Supplement. 1956 — F. Chittendon. · Oxford University Press · 1951 · ISBN - ↩︎Comprehensive listing of species and how to grow them. Somewhat outdated, it has been replaced in 1992 by a new dictionary (see [ 200 ]).
  4. [4]KemperCentreForHomeGardeningPlantFinder — Missouri Botanical Garden · http://www.mobot.org/gardeninghelp/plantfinder/ ↩︎Basic cultivation details, plant uses, habitat etc for several thousand species of plants, mainly from the temperate zone.
  5. [5]Trees and Shrubs Hardy in Great Britain. Vol 1 - 4 and Supplement. — Bean. W. · Murray · 1981 · ISBN - ↩︎A classic with a wealth of information on the plants, but poor on pictures.
  6. [6]A Manual of Indian Timbers. — Gamble. J. S. · Bishen Singh Mahendra Pal Singh · 1972 · ISBN - ↩︎First written in the 19th century, but still a classic, giving a lot of information on the uses and habitats of Indian trees. Not for the casual reader.
  7. [7]Propagation of Trees, Shrubs and Conifers. — Sheat. W. G. · MacMillan and Co · 1948 · ISBN - ↩︎A bit dated but a good book on propagation techniques with specific details for a wide range of plants.
  8. [8]The Reference Manual of Woody Plant Propagation. — Dirr. M. A. and Heuser. M. W. · Athens Ga. Varsity Press · 1987 · ISBN 0942375009 ↩︎A very detailed book on propagating trees. Not for the casual reader.
  9. [9]The RHS Gardener's Encyclopedia of Plants and Flowers — Brickell. C. · Dorling Kindersley Publishers Ltd. · 1990 · ISBN 0-86318-386-7 ↩︎Excellent range of photographs, some cultivation details but very little information on plant uses.
  10. [10]Flora of China — Missouri Botanical Garden Press; St. Louis. · 1994 · http://flora.huh.harvard.edu/china/ ↩︎An excellent, comprehensive resource in 25 volumes. In addition to the botanical information the flora also gives basic information on habitat and some uses. An on-line version is also available.
  11. [11]Rhododendron Species and Their Uses with Special Reference to Himalayas - A Review — Bhattacharyya D. · 2011 · ISBN 0975-2773 ↩︎A useful breif guide to the uses of Rhododendron species in the Himalayas
  12. [12]Plants and People of Nepal — Manandhar. N. P. · Timber Press. Oregon. · 2002 · ISBN 0-88192-527-6 ↩︎Excellent book, covering over 1,500 species of useful plants from Nepal together with information on the geography and peoples of Nepal. Good descriptions of the plants with terse notes on their uses.