Rhododendron indicum (Linnaeus) Sweet, Ericaceae

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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Risk assessment results:  Evaluate, score: 4 (Go to the risk assessment)

Other Latin names:  Azalea indica L.

Common name(s): [more details]

Chinese: gao yue du juan

Habit:  shrub

Description:  "Much-branched shrub, usually low and prostrate, though sometimes up to 2 m; young shoots covered with adpressed flattened chestnut-brown setose hairs.  Leaves dimorphic, chartaceous; spring leaves narrowly lanceolate to oblanceolate, 2-3 x 0.8 -1 cm, 2.3-3 x as long as broad, apex acute, base cuneate, margin remotely crenate-serrulate, ciliate, upper surface with scattered bristles, lower surface paler, with setose bristles restricted to midrib; summer leaves 10-18 x 3-5 mm, otherwise as for spring leaves; petioles 2-4 mm, clothed with adpressed chestnut-brown setose hairs.  Inflorescence 1-2-flowered; pedicels 5-10 mm, clothed with brown strigose hairs.  Calyx with brown strigose hairs, especially on lobe margins, lobes ovate to orbicular, c. 1 mm long.  Corolla broadly funnel-shaped, bright red to scarlet, occasionally rose-red, 30-50 mm; tube half the length of corolla, glabrous.  Stamens 5, as long as or slightly exceeding the corolla, filaments scabrid below.  Ovary densely covered with adpressed shining brown hairs; style glabrous.  Capsule oblong-ovoid, c. 10 mm long, densely strigose" (Chamberlain & Rae, 1990; pp. 119-120).

Habitat/ecology:  In Japan, "wooded river banks, etc.; also widely cultivated and sometimes escaping" (Chamberlain & Rae, 1990; pp. 119-120).

Propagation:  Seed

Native range:  Japan (S. and W. Honshu, Kyushyu) (Chamberlain & Rae, 1990; pp. 119-120).

Presence:

Pacific
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Nauru Nauru Island	Nauru Island	introduced cultivated	Thaman, R. R./Fosberg, F. R./Manner, H. I./Hassall, D. C. (1994) (p. 125) Rhododendron sp., rare, planted ornamental.

Pacific Rim
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
China China	China (People's Republic of)	introduced cultivated	Zhengyi, Wu/Raven, Peter H./Deyuan, Hong (2013) Widely cultivated in China.
Japan Japan	Japan	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
Singapore Singapore	Singapore (Republic of)	introduced cultivated	Chong, Kwek Yan/Tan, Hugh T. W./Corlett, Richard T. (2009) (p. 75) Cultivated only

Indian Ocean
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Australia (Indian Ocean offshore islands) Christmas Island Group	Christmas Island	introduced cultivated	Swarbrick, J. T. (1997) (p. 125)
Seychelles Seychelles Islands	Seychelles Islands	introduced	Invasive Species Specialist Group (2017)

Control:  If you know of control methods for Rhododendron indicum, please let us know.