Agapanthus Northern Star

Agapanthus ‘Northern Star’ is a wonderfully free-flowering variety, loved for its bold, summer colour and strong garden performance. It produces rounded heads of rich violet-blue blooms, each floret often marked with a darker purple stripe, and the buds can look noticeably deeper-toned before opening—giving the whole plant a really striking, “inky” finish. It’s also a brilliant choice for cut flowers, and the sturdy stems make it ideal for the middle of borders or as a statement in a large patio pot.

‘Northern Star’ is recognised as a top performer and is widely sold as an RHS AGM winner, so it’s a great pick if you want a reliable agapanthus that will come back year after year. Foliage can be semi-evergreen in milder areas and more likely to die back in colder spells—either way, it’s best protected from winter wet, especially in containers. 

Planting Instructions

When to Plant:

Plant in spring once the risk of severe frost has passed, or in early autumn while the soil is still warm and workable.

Where to Plant:
Choose a sunny position for the best flowering. Plant into well-drained soil that holds some moisture in summer. Agapanthus dislike sitting cold and wet in winter, so drainage is essential. Ideal for mixed borders, patio containers, and gravel or coastal-style planting.

How to Plant:

• Depth: Plant so the crown is at soil level (the top of the root mass sitting level with the surrounding soil).
• Spacing: Space plants 30–45 cm apart to allow clumps to develop.
• Soil Prep: Work in a little well-rotted compost for moisture-holding, but avoid heavy, waterlogged ground—improve drainage with grit if needed.

Watering:
Water well after planting. Keep the soil evenly moist while establishing. Once established, agapanthus cope well but will flower best with occasional watering during prolonged dry spells.

Aftercare Tips:

• Feed in spring and early summer with a high-potash feed to encourage flowering.
• Deadhead spent blooms for a tidier look, or leave seedheads for structure.
• In colder areas, add a winter mulch and protect from winter wet—containers can be moved to a sheltered spot.

Top Tip:
Agapanthus ‘Northern Star’ is superb in pots—and slightly “snug” roots can help encourage flowering. Place containers in the sunniest spot you have and protect from winter wet for the best results.

Plant Details

Flowering Period:
July - August (often into late summer in good seasons)

Height:
Approx. 90cm–1m

Spread:
Approx. 45cm

Foliage:
Semi-evergreen in mild areas; may die back in colder conditions