Rhododendron oldhamii Maxim.

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Peter Norris, enabling the use of The Rhododendron Handbook 1998


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

Recommended citation
'Rhododendron oldhamii' from the website Trees and Shrubs Online (treesandshrubsonline.org/articles/rhododendron/rhododendron-oldhamii/). Accessed 2024-06-16.



  • Rhododendron ovatosepalum Yamamoto

Other taxa in genus


(pl. calyces) Outer whorl of the perianth. Composed of several sepals.
The inner whorl of the perianth. Composed of free or united petals often showy.
Lowest part of the carpel containing the ovules; later developing into the fruit.
Lying flat against an object.
Bearing glands.
Egg-shaped; broadest towards the stem.
Generally an elongated structure arising from the ovary bearing the stigma at its tip.


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

Recommended citation
'Rhododendron oldhamii' from the website Trees and Shrubs Online (treesandshrubsonline.org/articles/rhododendron/rhododendron-oldhamii/). Accessed 2024-06-16.

Much-branched shrub, to 3 m; young shoots densely covered with spreading red-brown gland-tipped hairs intermixed with scattered more or less spreading flattened hairs. Leaves of two kinds; spring leaves deciduous, 3.5–6 × 1.8–2.5 cm, ovate-lanceolate, apex acute to mucronate, both surfaces covered with light brown pilose hairs that are longer on the midrib; summer leaves 1.5–2 × 0.8–1 cm; petioles covered with spreading pilose hairs. Pedicels covered with spreading gland-tipped red-brown hairs. Flowers 1–3 per inflorescence; calyx c.2 mm; corolla orange-red to coral-pink, funnel-shaped, 25–35 mm; stamens (8–)10; ovary densely covered with gland-tipped bristles, style glabrous. Flowering May-August. Royal Horticultural Society (1997)

Distribution  Taiwan

Habitat s.l.-2,450 m

RHS Hardiness Rating H3

Conservation status Least concern (LC)

An evergreen much-branched shrub 5 to 10 ft high; young shoots densely clothed with outstanding reddish hairs and some flattish bristles. Leaves elliptic to elliptic-ovate or oval, pointed, tapered at the base, 1 to 312 in. long, 12 to 112 in. wide, dull green and downy on both surfaces, especially beneath, wrinkled and rough to the touch above; stalk up to 12 in. long, bristly and hairy like the young shoots. Flowers in a terminal cluster of two to four. Calyx green, with rounded or ovate and pointed lobes up to 13 in. long, usually smaller; covered like the flower-stalk with glandular, sticky hairs. Corolla 2 in. wide, funnel-shaped at the base, spreading out into five rounded lobes 34 in. long, orange-red except on the upper lobes which are stained with pink and dotted with dark purple. Stamens ten, 12 to 1 in. long, red, with purple anthers and a downy base. Ovary bristly; style smooth, red, 112 in. long. Bot. Mag., t. 9059. (s. Azalea ss. Obtusum)

Native of Formosa only; discovered by Richard Oldham, the Kew collector, in 1864. First introduced for Messrs Veitch by Chas. Maries in 1878. I do not think any of his generation of plants survived, and the species was, no doubt, lost to cultivation until Wilson reintroduced it in 1918. In the past it has flowered in a cool greenhouse at Kew at such diverse seasons as February and August, but its normal time is April. In the open air there it will not survive even mild winters, and is only hardy in the south and west. It is handsome in flower, but not more so than many of the so-called ‘Indian’ azaleas (R. simsii) to which it is related, but easily distinguished by its larger leaves and the soft, spreading, frequently glandular hairs (not appressed flattened brisdes) on the young shoots. Wilson calls it the ‘common red-flowered azalea of Formosa’; it is found on that island from sea-level up to 8,500 ft.