Agapanthus
Agapanthus spp.
Agapanthus, or African lily, is a statuesque summer perennial producing bold globes of blue or white trumpet flowers on tall, strap-like stems from July to September. It thrives in the UK given a warm, sunny spot and well-drained soil — it is famously tolerant of drought once established and flowers best when its roots are slightly congested. Plant container-grown specimens in April–May, setting the crown just below the surface. In cold gardens, mulch deeply in autumn or grow in pots that can be moved into a cold greenhouse. Divide congested clumps every 4–5 years in spring for the best flowering. The tall flower heads are excellent in large arrangements.
Plan where to grow Agapanthus using our vegetable garden planner.
When to Plant Agapanthus
Plant agapanthus in March, April, May. It flowers from July to September.
Time to Flower Agapanthus
Expect flowers approximately 15 months after planting.
Companion Plants for Agapanthus
- English Lavender
Both thrive in sunny, free-draining spots, and lavender flowers alongside agapanthus in a hot border.
- Sage
Both are drought-tolerant once established and like the same sunny, well-drained conditions.
Expected Yield
A mature clump produces 10–20 flower stems each summer.
Pruning Agapanthus
Cut the faded flower stems down to the base unless you want the seed heads for decoration. Evergreen types need no cutting back; tidy deciduous types once the leaves die in autumn and mulch the crowns.
Common Problems with Agapanthus
Lots of leaves but no flowers
Agapanthus flowers best when slightly pot-bound or congested, and in full sun. Divide only every 4–5 years, and do not overfeed with nitrogen.
Foliage dies back in a cold winter
Deciduous types are hardier than evergreen. In cold areas, mulch with straw in autumn or grow in pots moved to a frost-free greenhouse.
Flower stems snap in wind
The tall hollow stems are brittle. Stake with a discreet cane, or plant in a sheltered corner protected from strong winds.
Agapanthus: common questions
When should I plant agapanthus in the UK?
Plant agapanthus from March to May.
How far apart should I plant agapanthus?
Space agapanthus about 45cm apart. It grows to around 80cm tall.
When does agapanthus flower?
Agapanthus usually flowers from July to September in the UK.
Does agapanthus come back every year?
Yes. Agapanthus is a perennial and comes back every year, dying back or slowing down over winter and regrowing in spring.
When should I prune agapanthus?
Cut the faded flower stems down to the base unless you want the seed heads for decoration. Evergreen types need no cutting back; tidy deciduous types once the leaves die in autumn and mulch the crowns.
What grows well with agapanthus?
Good companions for agapanthus include English Lavender and Sage. See the companion plants section above for why each one helps.
Is agapanthus frost hardy?
Only partly. Agapanthus is half-hardy: it copes with cold but not frost, so plant it out after the last frost (usually mid to late May) and protect it if frost is forecast.
Plan your agapanthus in the allotment planner
Drag and drop plants onto your plot and get personalised sowing reminders.
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