Oleander grows to 2–6 metres (7–20 feet) tall, with erect stem. The leaves are light green and very glossy when young, maturing to a dull dark green. The flowers grow in clusters at the end of each branch; they are white, pink to red, 2.5–5 cm (1–2 in) diameter. They are often, but not always, sweet-scented. The fruit is a long narrow pair of follicles 5–23 cm (2–9 in) long, which splits open at maturity to release numerous downy seeds.
The tree is native to temperate and subtropical areas.