RHS A herbaceous perennial 1-1.5m high with deciduous, strap-shaped green leaves, 3-5 cm wide and 15-45 cm long, and large heads of dark blue-violet buds which open to blue flowers in late summer
1-1.5 metres
0.5-1 metres
| Season | Stem | Flower | Foliage | Fruit |
|---|---|---|---|---|
| Spring | ||||
| Summer | ||||
| Autumn | ||||
| Winter |
Grow outside in mild areas in humus-rich, moisture-retentive but well-drained soil in full sun, and provide winter protection with a dry mulch; in colder areas, grow in containers in peat-free, loam-based compost, water freely when in growth but sparingly in winter, and apply a balanced liquid fertilizer monthly from spring until flowering; for more advice, see Agapanthus cultivation
Propagate by seed, sown at 13-15°C when ripe or in spring, and keep the seedlings in a frame for the first winter in frost-prone climates; or by division between spring and early summer, or in early autumn after plants have finished flowering
No pruning required except cutting back dead flower stems, but allow them to remain until spring, because the seedheads look attractive over winter
May be susceptible to slugs and snails and agapanthus gall midge but generally pest-free
May be susceptible to a virus