Mona Lavender is a hybrid of two South African species, Plectranthus saccatus and Plectranthus hilliardiae, developed for its combination of ornamental foliage and reliably late-season flowering. The shiny dark green leaves are striking on their own, with deep purple undersides that show whenever the plant moves in a breeze, but the real display comes when day length drops in fall and the lavender-purple flower spikes emerge in quantity. In zones 10 and 11, it grows outdoors year-round as a perennial to 1 to 2 feet tall and wide. In cooler climates, it functions beautifully as a container plant brought outside in summer and returned indoors well before frost.

Indoors, Mona Lavender needs partial shade and soil that is rich in organic matter and consistently moist but never waterlogged. Pinching the stems regularly keeps the plant dense and rounded rather than leggy. With adequate indirect light, the flowers can persist into spring, making this one of the more rewarding winter houseplants for anyone willing to give it a bright north or east-facing window. Propagation by stem cuttings is easy and quick, which makes it simple to maintain multiple plants or share divisions with other gardeners before the end of the growing season.