Aloe (Aloacae) This genus of perennials, herbs, shrubs or trees is invaluable for its colourful and long-lasting flowers, which have the bonus of being borne mostly in winter. There are around 350 species, and most are very drought-tolerant, as they come from dry parts of southern Africa and Arabia. Apart from their ornamental value, a few species are effective medicines: A. vera contains an antibiotic juice, and is still a popular remedy for burns. Keep a plant on your kitchen windowsill and dab the sap from the juicy leaves onto any burn. Recent studies have moved Aloe into its own family, Aloaceae, which is close to the larger, more diverse Asphodelaceae. All Aloe have tubular, red, yellow, or green flowers, and produce thick sweet nectar, which attracts sunbirds as well as other honey-eating birds.