It is a deciduous small tree growing to a height of 12 m (39 ft), rarely to 15 m (49 ft), with a trunk up to 30 cm (12 in), rarely 40 cm (16 in) in diameter; it is the largest species of lilac, and the only one that regularly makes a small tree rather than a shrub. The leaves are elliptic-acute, 2.5–15 cm (0.98–5.91 in) long and 1–8 cm (0.39–3.15 in) broad, with an entire margin, and a roughish texture with slightly impressed veins. The flowers are white or creamy-white, the corolla with a tubular base 0.16–0.24" (4–6 mm) long and a four-lobed apex 0.12–0.24" (3–6 mm) across, and a strong fragrance; they are produced in broad panicles 5–30 cm (2.0–11.8 in) long and 3–20 cm (1.2–7.9 in) broad in early summer. The fruit is a dry, smooth brown capsule (15–25 mm long), splitting in two to release the two winged seeds.