Syringa vulgaris is a large deciduous shrub or multi-stemmed small tree, growing to 6–7 m (20–23 ft) high. It produces secondary shoots from the base or roots, with stem diameters up to 20 cm (8 in), which in the course of decades may produce a small clonal thicket. The bark is grey to grey-brown, smooth on young stems, longitudinally furrowed, and flaking on older stems. The leaves are simple, 4–12 cm (2–5 in) and 3–8 cm broad, light green to glaucous, oval to cordate, with pinnate leaf venation, a mucronate apex, and an entire margin. They are arranged in opposite pairs or occasionally in whorls of three. The flowers have a tubular base to the corolla 6–10 mm long with an open four-lobed apex 5–8 mm across, usually lilac to mauve, occasionally white. They are arranged in dense, terminal panicles 8–18 cm (3–7 in) long. The fruit is a dry, smooth, brown capsule, 1–2 cm long, splitting in two to release the two-winged seeds.