Plectranthus hail from warm temperate to tropical areas of the world (particularly South Africa) 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.
The 'Cape Angels' series of Plectranthus was released here about five years ago, and they result from a cross between Plectranthus saccatus and Plectranthus hilliardiae to form compact shrubs about 60-80 cm tall. There are versions with white, pink, bluish, purple and magenta flowers, which are not always sold with names in nurseries. They are long flowering and are very easy-care plants for the shady garden, though they will also grow in sunny positions. The same cross of species resulted in the popular cultivar 'Mona Lavender', which has purple flowers and leaves with violet undersides. They are all good pot plants.
All these little shrubs make excellent companions to shrub and cane Begonia and Justicia carnea, and are also most useful to 'echo' nearby colours of foliage plants which grow well in shaded spots, such as the pink or white spots of the polka-dot plant (Hypoestes phyllostachya), the lilac markings of Persian shield (Strobilanthes dyeriana) or even just the white-striped leaves of the spider plant (Chlorophytum comosum 'Ocean'), which was the very first plant I ever grew: in a teapot!
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 plants dislike hard frosts, but if grown under a canopy of trees, will usually be well protected from milder frosts. They enjoy being mulched and fed occasionally but will tolerant neglect. 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.