The Temperate Database is in the process of being updated, with new records being added and old ones being checked and brought up to date where necessary. This record has not yet been checked and updated.
Common Name: Rhododendron
Rhododendron ponticum is a Evergreen Shrub up to 5.00 metres tall.
It has medicinal and miscellaneous uses.
Although no specific mention of toxicity has been seen for this species, it belongs to a genus where many members have poisonous leaves. The pollen of many if not all species of rhododendrons is also probably toxic, being said to cause intoxication when eaten in large quantities[
W. Europe to the Caucasus and Lebanon. Naturalized in Britain[
Rich forests under Fagus, Picea and Abies species, it is also found above the tree line[
]. Sandy and peaty soils in woods and open places in Britain[
Succeeds in a most humus-rich lime-free soils except those of a dry arid nature or those that are heavy or clayey[
]. Prefers a peaty or well-drained sandy loam[
]. A pH between 4.5 and 5.5 is ideal[
]. Succeeds in sun or shade, the warmer the climate the more shade a plant requires[
Hardy to about -15°c[
Plants are self-sowing aggressively in British woodlands and are often out-competing native trees by filling the understorey and preventing natural regeneration. They are considered to be a pernicious weed by many environmentalists.
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[
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[
A medicine made from the plant is used to treat heart and circulation malfunctions, but it should not be used without expert supervision[
Plants are being grown as a hedge at the RHS gardens in Wisley, Surrey[
]. It tolerates quite hard clipping[
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[