Isodon (Plectranthus) excisus

East Asia Mint Lamiaceae

A handsome late-season perennial with the slightly unruly charm typical of Isodon. Isodon excisus is native from the Russian Far East through Manchuria and northern China to Korea, growing in woodland margins, open forest, grassland and roadsides, generally at 550–1,100m. 

The name excisus refers to the characteristically notched leaf tips, often drawn out into a long, conspicuous terminal tooth. The foliage is aromatic when bruised, carried on branching stems which can reach around a metre. From July into August, loose panicles of small pale violet, purple or bluish flowers provide a welcome splash of colour when many perennials are beginning to run out of steam. 

A useful plant for the back of a late-summer border, particularly in sun or light shade and reasonably fertile, well-drained soil. Its Lamiaceae credentials make it attractive to bees and other insects, while its upright, slightly lax habit gives it a pleasantly naturalistic character.

Previously encountered under the names Rabdosia excisa and Plectranthus excisus, Isodon excisus is the currently accepted name. 

Height: 80–100cm | Spread: 50–70cm
Flowering: July–September | Foliage: Deciduous
Hardiness: H5 (-15 to -10°C)