Rosebay Rhododendron, Great laurel
Rhododendron maximum

Family: Ericaceae

What it is like

Rhododendron maximum is an evergreen Shrub growing to 3.5 m (11ft 6in). See above for USDA hardiness. It is hardy to UK zone 3. It is in leaf all year, in flower from June to July, and the seeds ripen in October. The species is hermaphrodite (has both male and female organs) and is pollinated by Bees. Suitable for: light (sandy) and medium (loamy) soils and prefers well-drained soil. Suitable pH: mildly acid soils and can grow in very acid soils. It can grow in semi-shade (light woodland). It prefers moist soil.

Height (m): 3.5

Where it is found

Damp places along streams, edges of bogs and ponds, woods and mountain slopes to 900 metres, often forming impenetrable thickets.

Eastern N. America - Nova Scotia and south to Georgia and Alabama.

Conservation Status:

Countries/locations it is found in

How it is used

Food

Rating: 0

Medicine

Rating: 1

The poulticed leaves are used to relieve arthritic pain, headaches etc. A decoction of the leaves is occasionally employed internally in domestic practice in the treatment of rheumatism. The leaves are taken internally in controlled dosage for the treatment of heart ailments. Caution is advised, see the notes above on toxicity.

Analgesic: Relieves pain.

Antirheumatic: Treats rheumatism.

Cardiac: Used in the treatment of heart problems.

Other

Rating:

Wood - fine-grained, hard, heavy, strong, rather brittle. It weighs 39lb per cubic foot. Used for tool handles and as a boxwood (Buxus spp.) substitute in engraving.

Wood: A list of the trees and shrubs that are noted for having useful wood.

How it is grown

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. Succeeds in sun or shade, the warmer the climate the more shade a plant requires. A pH between 4.5 and 5.5 is ideal. Hardy to about -30°c. 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.

Propagating it: 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 April. 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.

Best place to grow: Woodland Garden Dappled Shade; Shady Edge;

Habit: Shrub

Hardiness: 3-7

Growth:

Soil: Light (sandy), medium

Shade: Semi-shade

Moisture: Moist

Things to keep in mind

The leaves are poisonous. Ingestion can cause convulsions and coma. The pollen of many if not all species of rhododendrons is also probably toxic, being said to cause intoxication when eaten in large quantities.

Its other names

Local names

Synonyms

R. procerum.