Oleander, rose bay

Leaves: petiole 2–7 mm, sparsely pubescent or glabrous; blade oblong-lanceolate, 2–15(–30) × 0.5–2.5(–3.5) cm, coriaceous, base cuneate, margins revolute, apex acuminate, surfaces pubes­cent abaxially, very sparsely pubescent or glabrous adaxially. Peduncles 3–6 cm, sparsely pubescent. Pedicels 5–8 mm, pubescent. Flowers: calyx lobes lanceolate to ovate-lanceolate, 5–7 mm, pubes­cent; corolla glabrous abaxially, eglandular-pubescent adaxially, tube 8–12 × 2–3 mm, throat 5–10 × 4–7 mm, lobes spreading, obliquely obovate, 15–25 × 10–20 mm. Follicles 8–15 × 1–1.5 cm. Seeds 7–10 × 1.5–2 mm, densely pubescent. 2n = 22.

Flowering spring–summer; fruiting summer–fall. Disturbed areas, roadsides, old homesites; 0–600 m; introduced; Ala., Ariz., Calif., Ga., La., Miss., N.C., S.C., Tex.; Eurasia; Africa; widely cultivated in tropical and subtropical regions.

Nerium oleander is cultivated in warmer parts of the United States and has become sporadically naturalized from North Carolina to Florida and Texas, and in Arizona and California. The plant is widely recognized as one of the most poisonous cultivated species due to the presence of cardiac glycosides that can cause nausea, vomiting, abdominal pain, diarrhea, cardiac arrhyth­mia, and potassium imbalance (V. Bandara et al. 2010), although the number of human fatalities resulting from accidental ingestion of leaves and/or flowers is surpris­ingly small (S. D. Langford and P. J. Boor 1996).