Which agapanthus varieties flower for the longest time?

Which Agapanthus varieties flower for the longest?

Which Agapanthus are the latest to flower?

Agapanthus are generally reported to flower between June and September. When discussing flowering period, as with other flowers, it is important to qualify this according to region (warmer or cooler climate), sunlight and varieties (see last section).
But some horticultural cultivars do flower later. Examples include:

• Agapanthus ‘Blue Moon’‘: this Blue Moon blooms from late July to August, producing small, very pale blue flowers with greyish tints. It is ideal for growing in pots, reaching up to 80 cm, on sturdy stems that give it an attractive habit. It is a hybrid of Agapanthus praecox, which gives it slightly broader leaves. It is hardy down to -6.5°C (in the ground);
• ‘Broadleigh Babe’: a pretty variety popular with English gardeners, about 90 cm tall, with deep-blue flowers borne on strong scapes. The flowers are pendulous, and flowering occurs in late summer.
• ‘Queen Mum‘ : rather tall (1 m in flower), it produces unusual umbels, mauve-blue and white bicolour, and flowers in August; its foliage is evergreen to semi-evergreen depending on climate.
• ‘Windsor Grey‘ : this agapanthus also flowers later in the summer, up to September. White, as the name suggests, it has greyish tones. It adapts very well to growing in pots, although in the ground it can reach 1 m in height.
• ‘Headbourne Blue‘ : a late-summer, deciduous agapanthus, particularly valued for its cold tolerance.
• ‘Loch Hope’ : named after a Scottish Highland loch, Agapanthus ‘Loch Hope’ is one of the latest agapanthus to flower. Its superb deep-blue inflorescences can be enjoyed from August to September in most regions. With deciduous foliage, it is somewhat less susceptible to cold. It is also one of the tallest, reaching up to 1.5 m in full flower!

Agapanthus ‘Blue Moon’ on left, and ‘Queen Mum’ on right (photo Wikimedia Commons ©Acabashi)

Which Agapanthus are repeat flowering?

Another way to obtain later flowering in Agapanthus is to include a few that are repeat flowering in late summer. They will bloom in waves if conditions are favourable. Few are concerned here:

• ‘Purple Delight’ : deep violet-blue, evergreen foliage, reaches 90 cm in flower.
• ‘Charlotte‘ : one of the first cultivars developed for repeat flowering, particularly reliable, pale blue streaked with darker.
• The Everpanthus series Agapanthus^® (see following section) : ‘Poppin Star‘ an evergreen Agapanthus with mauve flowers streaked with violet, reaching 60 cm, repeats strongly throughout season and grows quickly to produce a rapid, showy display; ‘Ever Sapphire’ (syn. Andbin), known to repeat in October if mild, and the Agapanthus ‘Sparkle’, very repeat flowering up to October.

Agapanthus ‘Ever Sapphire’, ‘Charlotte’ and ‘Poppin Star’

Which agapanthus are long-flowering?

We cannot, as in warm climates, obtain such a long flowering period for Agapanthus in temperate climates; they generally flower for a maximum of five weeks.

That said, some Agapanthus are showstoppers, standing out for a remarkable flowering period, thanks to sterile varieties or recent innovations in the world of Agapanthus :

• ‘Everpanthus Midnight Sky‘ : part of the Everpanthus^® series, a major innovation and breakthrough from South African breeders (CND Nursery) who worked for years on genetic selection to breed plants with distinctive traits. The result? a record-long flowering period and repeat-flowering. Everpanthus^® varieties indeed offer continuous flowering for 17 weeks, from spring until late summer, even into early autumn. They are also repeat-flowering, producing several waves of flowers after the first main flush; ‘Midnight Sky’ is notable for its deep, intense blue;
• ‘Black Jack’ : awarded by the Royal Horticultural Society in 2023 for its abundant flowering, this 90 cm Agapanthus produces many very dense umbels, lasting through much of summer, sometimes into September;
• ‘Poppin Purple‘ : also prized for its long flowering and intense, almost purplish violet colour. Well suited to pots (60 cm).

Sterile varieties : some Agapanthus varieties, such as the Agapanthus ‘Headbourne Hybrids’, the Everpanthus® series, Agapanthus ‘Snow Storm’ or Agapanthus ‘Blue Storm’, produce few or no seeds. This prolongs their flowering period, as the plant does not divert energy into forming fruit.

Agapanthus ‘Midnight Sky’ and ‘Black Jack’ – ©Plantipp

Promesse de fleurs tips to optimise agapanthus flowering

Repeat flowering depends mainly on variety and care provided, while flowering duration will always be strongly influenced by climate. In warm climates such as South Africa, where they originate, or subtropical zones like Madeira, agapanthus benefit from optimal conditions to bloom for an extended period.

Of course, flowering period is not an exact science and will vary, especially according to factors that influence it most:

• Climate: warm climates (Mediterranean (Provence, Languedoc, French Riviera) mild south-west (Basque Country, southern Atlantic coast)) are where agapanthus are most likely to repeat flowering, to flower continuously and late into the season.
• Exposure: full sun is necessary for abundant, long-lasting flowering. Avoid windy locations.
• Soil: must be well drained, rich and kept cool, slightly acidic.
• Watering: moderate but regular in summer, about 3 to 5 L per plant, once a week, especially during growth and flowering (remember that in South Africa it does not rain when they flower during the dry summer).
• Cultural practices: include removal of spent flower stalks. Cutting flower stalks after flowering prevents plant wasting energy on seed production, which can encourage repeat flowering.