The common names for this plant include, Painted nettle, Scaredy Cat plant and Piss off plant; botanically it can be found as Plectranthus caninus or Coleus canina.
Like most members of the mint family Plectranthus caninus is aromatic, mainly when touched or brushed against or when in hot sun. Some say it smells like dog urine, others like marijuana but in either case the aroma is not pleasant, especially to cats, squirrels and other mammals. It is native to South Africa and is not frost resistant. A thick layer of mulch in autumn should give the roots extra protection through the winter so that it reshoots in spring.
The Scaredy Cat plant has the typical square stems of the mint family. Its serrated edged leaves, which are arranged in pairs on the bushy stems, are a grey-green colour and covered in fine, soft hairs. The blue or lilac flowers form in spikes at the end of the branches and are about 7cm long. It is drought resistant once established but with regular watering during the hottest months, will reach approximately 45cm high by about 40cm across. Propagation is very easy, cuttings root easily in water and stems will root where they touch the ground.
It can be grown in a container and moved around to deter cats from corners of your garden or grown in the border where it will eventually spread. Unlike culinary mint, Plectranthus caninus is not invasive but is a useful and attractive ground cover plant for dry areas in semi-shade. In full sun the aroma from the leaves is stronger although some people don't find it offensive.
To increase the power of its deterrent capabilities, pinching off the flower spikes as they appear will result in more leaves and bushier growth. It may be a good idea to wear gloves though, as the scent is lingering on both skin and fabrics.