Plant of the week: Agapanthus

The Nile lily is a real joy that looks super-stylish in the summer garden

Agapanthus are riding a tidal wave of horticultural popularity and rightly so, as they’re a star performer of summer borders and containers. Hailing from South Africa, they’ve been grown in UK gardens since A. praecox was introduced in 1687.

Agapanthus are fleshy-rooted, clump-forming perennials that are divided into two groups; deciduous types, which lose leaves in winter and are the hardiest, and semi-evergreen to evergreen types, which retain leaves and are more tender. Habits vary from short miniatures with fine leaves, just 30-45cm (1-1½ft) high, to 2.1m (7ft) giants, with strap-like foliage. Flowering is July and August, but larger varieties can bloom into September and October. Flowers, which appear in loose umbels, vary in colour from near black through purple, grey-blue, royal blue to white. Some are bi-coloured or have a median blue line down each petal. Some recent introductions also sport pink tinges to petals. Flowers are usually flared trumpets or pendant tubes, as in the distinctive A. inapertus pendulus, a parent of ‘Black Magic’.

They make great pot plants, but to flower reliably they need growing in isolation, rather than in mixed plantings. They also need to settle and form sizeable clumps, eventually being allowed to become pot-bound. Newly potted plants usually produce foliage at the expense of flowers. The same goes for plants in borders. They need space, light and air, rather than being over-topped or shaded by other perennials. They’ll grow in most moist, well-drained soils, requiring sun or light shade. Work a dressing of compost into the soil and apply a spring dressing of a balanced high-potash fertiliser.

They can be grown from seed, but varieties won’t be true to type. Division of the clump is the best method, lifting in spring or early summer or early autumn after flowering, separating the clump

into rooted sections with two to three growth points.