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.
Swedish ivy (Plectranthus verticillatus, ht 40 cm) is a very easily grown groundcover and originates in southern Africa. It will grow far and wide in dry, neglected places to produce a lush rug of shiny green scallop-shell leaves. It has a modest froth of white flowers in autumn. It is easy to contain if it spreads too far, as it has a shallow root system. It makes an excellent carpet beneath autumn-flowering Camellia sasanqua, shrub and cane Begonia and Justicia carnea, or just in wild places in the garden beneath trees. Like other groundcover Plectranthus species, it looks effective growing in a hanging basket. There are different forms around - there is one with a burgundy underside to the leaves is very attractive, and I have a white-variegated leaf form, which is quite unusual. In warmer climates than Sydney, this Plectranthus may become a pest, and should not be planted near bushland.
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 no matter what! It is very easily propagated from cuttings in spring and autumn.