Rosmarinus is a small genus of woody, perennial herbs with fragrant evergreen needle-like leaves in the family Lamiaceae, native to the Mediterranean Basin.
Plants to 2 m tall. Bark dark gray, irregularly fissured, exfoliating, young branches densely white stellate-tomentulose. Leaves tufted on branches, sessile to short petiolate; leaf blade 1-2.5 cm × 1-2 mm, leathery, adaxially somewhat shiny, subglabrous, abaxially densely white stellate-tomentose, base attenuate, margin entire, revolute, apex obtuse. Calyx ca. 4 mm, densely white stellate tomentose and glandular outside, upper lip subcircular, teeth of lower lip ovate-triangular. Corolla blue-purple, less than 1 cm, sparsely pubescent outside, tube slightly exserted, apex of upper lip 2-lobed, lobes ovate, middle lobe of lower lip constricted at base into claw, lateral lobes oblong.It also tends to be lower-growing, often under 25 cm tall and prostrate, and never exceeding 1 m tall (R. officinalis can reach 1.5 m, exceptionally 2 m, tall).