Few plant lovers forget their first glimpse of Agapanthus. In full bloom, its umbels, ranging in colour from deep violet-blue to pure white, spell love at first sight, which may account for its botanical name, an adaptation of the Greek words for love (agape) and flower (anthos). Pink-flowering forms are also being developed, but they should not be confused with a similar-looking species, Tulbaghia violacea.
Agapanthus has numerous common names, including African blue lily and lily-of-the-Nile. This genus is native to South Africa, with evergreen species found in areas with precipitation just in winter (Western Cape) or year-round (Eastern Cape), and hardier deciduous types restricted to locales with summer rains.
While only marginally hardy in even the mildest regions of Canada—including some parts of southern Ontario and coastal British Columbia—Agapanthus has found a niche in the Canadian landscape as a container plant. It requires a fast-draining growing medium, pots with drainage holes, full sun, regular watering (keep slightly moist) and, during active growth, a weekly application of a one-quarter-strength solution of a balanced fertilizer, such as 14-14-14. Continue feeding for about a month after flowering to help the formation of next year's buds. Evergreen forms, such as 'Streamline', can be overwintered in a slightly cool, bright room and treated as houseplants. Deciduous cultivars, such as 'Blue Triumphator', should be moved to a cool, dark, indoor location once their leaves are touched by the first frost. Water deciduous varieties minimally, without allowing the soil to dry out completely (increase your watering once leaves emerge again in late winter or early spring). Whether grown in a container or in the ground, all Agapanthus should be divided every four years or so—deciduous types in March, just before they start growing, and evergreen forms immediately after flowering.
Agapanthus are available as bare-root rhizomes or, at specialty nurseries, as rooted plants. Rhizomes should be planted 2.5 centimetres deep in containers, ideally one per 30-centimetre pot or three per 45- to 50-centimetre pot. In my experience, individual plants bloom better when root-bound (the exception being old, overcrowded plants that have not been divided).