This perennial plant is often mistaken for a Salvia. It has large, grey-green textured leaves shaped like arrowheads; they have a sharp medicinal - though not unpleasant - scent. From late February to May it sends up long spires of burgundy flowers, held in dark calyces on deep pinkish stems. Mine grows to about 1.5m tall and I cut it back hard at the end of winter, when new growth appears at the base. From what little I have been able to find out about it, it possibly originates in Chile and is a member of the Lamiaceae family of plants. There are other species: I have grown Lepechinia hastata in the past, a winter-flowering version, which I did not like as much as L. salviae.
It looks at home grown among Salvia specimens (especially blue-flowered ones) and other denizens of a semi-tropical border. I have mine growing nearby a very dark purple-brown form of Iresine herbstii, which echoes the dark calyces of the Lepechinia blooms. I grow Brillantaisia behind it and this forms a long-lasting composition through late summer and autumn. I grow my specimen in sun, with reasonable soil, but I think they could survive a poorer position, and I have heard that it can flower in a part-shade position. Propagation is by cuttings, which may be slow to strike. Don't cover the cuttings - place in shade and keep reasonable moist. The plant also may self-seed; these plants can be easily dug up and repotted, and given to those who admire it in your garden!