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Useful Temperate Plants

Rhododendron ponticum

L.

Ericaceae

+ Synonyms

Anthodendron ponticum (L.) Rchb.

Azalea arborea L.

Azalea gandavensis K.Koch

Azalea lancifolia (Moench) Kuntze

Hymenanthes pontica (L.) H.F.Copel.

Rhododendron gandavense Rehder

Rhododendron myrtifolium Lodd.

Azalea baetica (Boiss. & Reut.) Kuntze

Rhododendron baeticum Boiss. & Reut.

Common Name: Rhododendron

No Image.

General Information

Rhododendron ponticum is an evergreen shrub or small tree that can grow from 2 - 8 metres tall. A compact shrub when growing in open areas, it adopts a larger spread in the shade of a woodland[
1093
Title
Invasive Species Compendium
Publication
 
Author
 
Website
http://www.cabi.org
Publisher
 
Year
0
ISBN
 
Description
An immense resource - in depth information on over 900 species of invasive plants (it also has information on animals, fungi etc).
].
The plant is harvested from the wild for local use as a medicine and source of materials. It is often grown as an ornamental, where it can be used as an effective hedge.
Rhododendron ponticum has often been cultivated outside its native range as an ornamental and, in many areas of Europe, it has escaped from cultivation and become naturalized. It is particularly problematic in Britain, where plants are self-sowing aggressively in woodlands, often out-competing native trees by filling the understorey and preventing natural regeneration. Left untreated, the plant can end up producing a virtual monoculture. The species is considered to be a pernicious weed by many environmentalists[
1093
Title
Invasive Species Compendium
Publication
 
Author
 
Website
http://www.cabi.org
Publisher
 
Year
0
ISBN
 
Description
An immense resource - in depth information on over 900 species of invasive plants (it also has information on animals, fungi etc).
].

Known 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[
1668
Title
Grayanotoxin Poisoning: ‘Mad Honey Disease’ and Beyond
Publication
Cardiovasc Toxicol (2012) 12:208-215
Author
Jansen S.A. et al
Website
https://doi.org/10.1007/s12012-012-9162-2
Publisher
 
Year
2012
ISBN
 
Description
An in-depth review of the literature on the toxic effects of a toxin widely found in the family Ericaceae
].

Botanical References

11
Title
Trees and Shrubs Hardy in Great Britain. Vol 1 - 4 and Supplement.
Publication
 
Author
Bean. W.
Publisher
Murray
Year
1981
ISBN
-
Description
A classic with a wealth of information on the plants, but poor on pictures.
,
17
Title
Flora of the British Isles.
Publication
 
Author
Clapham, Tutin and Warburg.
Publisher
Cambridge University Press
Year
1962
ISBN
-
Description
A very comprehensive flora, the standard reference book but it has no pictures.
,
200
Title
The New RHS Dictionary of Gardening. 1992.
Publication
 
Author
Huxley. A.
Publisher
MacMillan Press
Year
1992
ISBN
0-333-47494-5
Description
Excellent and very comprehensive, though it contains a number of silly mistakes. Readable yet also very detailed.

Range

Southern Europe to western Asia - Portugal, Spain, Bulgaria, Turkey, Lebanon and the Caucasus

Habitat

Rich forests under Fagus, Picea and Abies species, it is also found above the tree line[
11
Title
Trees and Shrubs Hardy in Great Britain. Vol 1 - 4 and Supplement.
Publication
 
Author
Bean. W.
Publisher
Murray
Year
1981
ISBN
-
Description
A classic with a wealth of information on the plants, but poor on pictures.
]. Sandy and peaty soils in woods and open places in Britain[
17
Title
Flora of the British Isles.
Publication
 
Author
Clapham, Tutin and Warburg.
Publisher
Cambridge University Press
Year
1962
ISBN
-
Description
A very comprehensive flora, the standard reference book but it has no pictures.
].

Properties

Medicinal Rating *  *
Other Uses Rating *  *
HabitEvergreen Shrub
Height5.00 m
PollinatorsInsects
Cultivation StatusOrnamental, Wild

Cultivation Details

Rhododendron ponticum is a very cold-tolerant plant, when fully dormant it can withstand temperatures down to about -15°c[
184
Title
Shrubs.
Publication
 
Author
Phillips. R. & Rix. M.
Publisher
Pan Books
Year
1989
ISBN
0-330-30258-2
Description
Excellent photographs and a terse description of 1,900 species and cultivars.
]. 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[
200
Title
The New RHS Dictionary of Gardening. 1992.
Publication
 
Author
Huxley. A.
Publisher
MacMillan Press
Year
1992
ISBN
0-333-47494-5
Description
Excellent and very comprehensive, though it contains a number of silly mistakes. Readable yet also very detailed.
].
Succeeds in full sun, but is also very tolerant of deep shade, even almost closed canopy conditions do not prevent this species from growing[
1093
Title
Invasive Species Compendium
Publication
 
Author
 
Website
http://www.cabi.org
Publisher
 
Year
0
ISBN
 
Description
An immense resource - in depth information on over 900 species of invasive plants (it also has information on animals, fungi etc).
]. Prefers a moist but well-drained, humus-rich lime-free soil. Prefers a peaty or well-drained sandy loam[
1
Title
RHS Dictionary of Plants plus Supplement. 1956
Publication
 
Author
F. Chittendon.
Publisher
Oxford University Press
Year
1951
ISBN
-
Description
Comprehensive listing of species and how to grow them. Somewhat outdated, it has been replaced in 1992 by a new dictionary (see [200]).
]. A pH between 4.5 and 5.5 is ideal[
1
Title
RHS Dictionary of Plants plus Supplement. 1956
Publication
 
Author
F. Chittendon.
Publisher
Oxford University Press
Year
1951
ISBN
-
Description
Comprehensive listing of species and how to grow them. Somewhat outdated, it has been replaced in 1992 by a new dictionary (see [200]).
]. Succeeds in sun or shade, the warmer the climate the more shade a plant requires[
184
Title
Shrubs.
Publication
 
Author
Phillips. R. & Rix. M.
Publisher
Pan Books
Year
1989
ISBN
0-330-30258-2
Description
Excellent photographs and a terse description of 1,900 species and cultivars.
,
200
Title
The New RHS Dictionary of Gardening. 1992.
Publication
 
Author
Huxley. A.
Publisher
MacMillan Press
Year
1992
ISBN
0-333-47494-5
Description
Excellent and very comprehensive, though it contains a number of silly mistakes. Readable yet also very detailed.
].
Succeeds in a woodland though, because of its surface-rooting habit[
200
Title
The New RHS Dictionary of Gardening. 1992.
Publication
 
Author
Huxley. A.
Publisher
MacMillan Press
Year
1992
ISBN
0-333-47494-5
Description
Excellent and very comprehensive, though it contains a number of silly mistakes. Readable yet also very detailed.
], it does not compete well with surface-rooting trees[
1
Title
RHS Dictionary of Plants plus Supplement. 1956
Publication
 
Author
F. Chittendon.
Publisher
Oxford University Press
Year
1951
ISBN
-
Description
Comprehensive listing of species and how to grow them. Somewhat outdated, it has been replaced in 1992 by a new dictionary (see [200]).
]. 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[
200
Title
The New RHS Dictionary of Gardening. 1992.
Publication
 
Author
Huxley. A.
Publisher
MacMillan Press
Year
1992
ISBN
0-333-47494-5
Description
Excellent and very comprehensive, though it contains a number of silly mistakes. Readable yet also very detailed.
].
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[
200
Title
The New RHS Dictionary of Gardening. 1992.
Publication
 
Author
Huxley. A.
Publisher
MacMillan Press
Year
1992
ISBN
0-333-47494-5
Description
Excellent and very comprehensive, though it contains a number of silly mistakes. Readable yet also very detailed.
].
Plants in this genus are notably susceptible to honey fungus[
200
Title
The New RHS Dictionary of Gardening. 1992.
Publication
 
Author
Huxley. A.
Publisher
MacMillan Press
Year
1992
ISBN
0-333-47494-5
Description
Excellent and very comprehensive, though it contains a number of silly mistakes. Readable yet also very detailed.
].

Edible Uses

None known

Medicinal

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

A medicine made from the plant is used to treat heart and circulation malfunctions, but it should not be used without expert supervision[
9
Title
Edible and Medicinal Plants.
Publication
 
Author
Launert. E.
Publisher
Hamlyn
Year
1981
ISBN
0-600-37216-2
Description
Covers plants in Europe. a drawing of each plant, quite a bit of interesting information.
].

Agroforestry Uses:

Plants are being grown as a hedge at the RHS gardens in Wisley, Surrey[
29
Title
Hedges and Screens.
Publication
 
Author
Shepherd. F.W.
Publisher
Royal Horticultural Society.
Year
1974
ISBN
0900629649
Description
A small but informative booklet giving details of all the hedging plants being grown in the R.H.S. gardens at Wisley in Surrey.
]. It tolerates quite hard clipping[
200
Title
The New RHS Dictionary of Gardening. 1992.
Publication
 
Author
Huxley. A.
Publisher
MacMillan Press
Year
1992
ISBN
0-333-47494-5
Description
Excellent and very comprehensive, though it contains a number of silly mistakes. Readable yet also very detailed.
].

Other Uses

The reddish wood is firm, hard, beautifully patterned. It is suitable for turning[
74
Title
Flora of the USSR.
Publication
 
Author
Komarov. V. L.
Website
http://www.biodiversitylibrary.org
Publisher
Israel Program for Scientific Translation
Year
1968
ISBN
-
Description
An immense (25 or more large volumes) and not yet completed translation of the Russian flora. Full of information on plant uses and habitats but heavy going for casual readers. It can be downloaded from the Internet.
].

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[
200
Title
The New RHS Dictionary of Gardening. 1992.
Publication
 
Author
Huxley. A.
Publisher
MacMillan Press
Year
1992
ISBN
0-333-47494-5
Description
Excellent and very comprehensive, though it contains a number of silly mistakes. Readable yet also very detailed.
]. 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[
78
Title
Propagation of Trees, Shrubs and Conifers.
Publication
 
Author
Sheat. W. G.
Publisher
MacMillan and Co
Year
1948
ISBN
-
Description
A bit dated but a good book on propagation techniques with specific details for a wide range of plants.
].
Cuttings of half-ripe wood, August in a frame. Difficult[
78
Title
Propagation of Trees, Shrubs and Conifers.
Publication
 
Author
Sheat. W. G.
Publisher
MacMillan and Co
Year
1948
ISBN
-
Description
A bit dated but a good book on propagation techniques with specific details for a wide range of plants.
].
Cite as: Temperate Plants Database, Ken Fern. temperate.theferns.info. 2019-09-22. <temperate.theferns.info/plant/Rhododendron+ponticum>

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