Aloysia triphylla

A deciduous shrub (naturally a small tree), reaching in the southern parts of the British Isles 10 to 15 ft or more in height; young shoots angular. Leaves mostly in threes, very fragrant, lance-shaped; usually 3 to 4 in. long, 1⁄2 to 7⁄8 in. wide; wedge-shaped at the base, taper-pointed, not toothed; both surfaces glandular, especially the upper one, pale green; margins set with appressed bristles. The veins are parallel, springing at right angles from the midrib. Flowers numerous, small, pale purple, produced in August in slender, terminal, stalked, downy panicles, 3 to 5 in. high; corolla tubular, 1⁄6 in. long, downy, as is also the cylindrical, toothed calyx.

Native of Chile; introduced in 1784. Near London this well-known shrub needs the protection of a wall, and is often grown in cold conservatories for the pleasant lemon-like scent of the leaves. In the Isle of Wight and the Channel Islands it becomes a large bush without any protection. Easily increased by summer cuttings.