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Rhododendron flammeum (Michx.) Sarg.

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Kindly sponsored by
Peter Norris, enabling the use of The Rhododendron Handbook 1998

Credits

Article from Bean's Trees and Shrubs Hardy in the British Isles

Recommended citation
'Rhododendron flammeum' from the website Trees and Shrubs Online (treesandshrubsonline.org/articles/rhododendron/rhododendron-flammeum/). Accessed 2025-04-21.

Family

  • Ericaceae

Genus

Synonyms

  • Azalea calendulacea var. flammea Michx.
  • Rhododendron speciosum (Willd.) Sweet, not Salisb.
  • Azalea nudiflora var. coccinea Ait.

Other taxa in genus

Glossary

corolla
The inner whorl of the perianth. Composed of free or united petals often showy.
glandular
Bearing glands.
precocious
The production of flowers/inflorescences prior to leaf emergence. (Cf. coetaneous serotinous.)

Credits

Article from Bean's Trees and Shrubs Hardy in the British Isles

Recommended citation
'Rhododendron flammeum' from the website Trees and Shrubs Online (treesandshrubsonline.org/articles/rhododendron/rhododendron-flammeum/). Accessed 2025-04-21.

Deciduous shrub, to 2.5 m; young twigs densely covered with eglandular hairs. Leaves (3–)3.9–6.3(–8.2) × 1.5–2.4(–2.7) cm, ovate or obovate to elliptic, lower surface densely eglandular-hairy or glabrous. Flower bud scales with outer surface covered with unicellular hairs, rarely glabrous. Flowers with an acrid fragrance, appearing before or with the leaves, 6–11, in a shortened raceme; calyx 1–3(–5) mm; corolla scarlet to orange, funnelform, tube abruptly expanding into the limb, outer surface of corolla covered with eglandular hairs, 27–45 mm. Capsule with eglandular-hairs. Flowering April. Royal Horticultural Society (1997).

Distribution  United States SE

Habitat s.l.-500 m

RHS Hardiness Rating H5

Conservation status Vulnerable (VU)

Taxonomic note R. flammeum differs from the allied R. prunifolium and R. cumberlandense in the precocious flowers that appear before the leaves. Royal Horticultural Society (1997)

This, the most brilliantly coloured of all American azaleas, was in cultivation as long ago as 1789, and was figured in the Botanical Magazine in 1792 (t. 180). Old plants may still be in gardens, but the name appears to have been lost. It was in cultivation at Kew in 1881 as ‘Azalea nudiflora coccinea’. Plants were sent to England by Professor Sargent in 1916. It has been confused with R. calendulaceum, but differs in the slender corolla-tubé which is not glandular as it is in that species. The flowers also are more numerous in the truss, and the colour ‘is always scarlet or bright red and never varies to yellow’ (Rehder). R. calendulaceum is a more northern shrub and hardier, but, as may be gathered from what is stated above, R. flammeum is quite hardy in this country. No doubt many of our richest- coloured deciduous azaleas owe much of their vivid red and scarlet hues to this species.

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