A tender to borderline hardy, upright, branching, woody-based perennial, often grown as an annual, with ovate, hairy, toothed, aromatic, mid-green leaves and dark purple stems bearing whorled spikes of fragrant, two-lipped, dark purple flowers from early summer into autumn.
Height 1.2m (4ft), Spread 1m (3ft), 2-5 years to maturity.