Plectranthus hail from warm temperate to tropical areas of the world and grow in shadier parts of the garden under trees in very ordinary soil where many plants do not thrive. They grow quickly and are tolerant of drought and root-competition.
This variegated form of Plectranthus forsteri, which has the cultivar name of 'Marginatus', is a semi-trailing plant, growing to 25cm tall and over a metre wide. Its scalloped-edged leaves are nicely variegated with creamy-white margins. It has spires of pale mauve or white flowers in autumn. It will grow in the most uncongenial shady places and can form a dense carpet under trees or shrubs, and brings light into gloomy areas. It is effective when planted nearby white autumn flowers so that its leaves can echo their colour - for example, Camellia sasanqua 'Setsugekka', white-bloomed shrub and cane Begonia, or Justicia carnea.
The stems should be cut back fairly hard after flowering (or in early spring in cooler areas if there is the risk of frosts). The plant dislikes hard frosts, but if grown under a canopy of trees, will usually be well protected from milder frosts. It enjoys being mulched and fed occasionally but is really a plant that will grow despite being neglected! It is very easily propagated from cuttings in spring and autumn. All Plectranthus need to be replaced by new cuttings every so often as they get a bit straggly after a few years. I find this species rather prone to the attacks odf flea beetles, which disfigure the foliage with tiny marks. Neem oil could be tried as a control.