Agapanthus

Agapanthus africanus

Clump-forming perennial with long-stemmed blue or white flower heads in summer.

Hardiness ratings

Agapanthus hardiness across the four zone systems
SystemRatingTemperature rangeHow to read it
USDA hardiness zone Zone 8–11 −12.2 °C to 10 °C Plant tolerates down to this zone
RHS hardiness rating H3 −5 °C to 1 °C Plant needs at least this level of cold tolerance
Canadian plant hardiness zone Zone 8–9 −7 °C and warmer Plant tolerates down to this zone
Australian (ANBG) zone Zone 4–7 0 °C and warmer Plant tolerates down to this zone

About Agapanthus

Agapanthus is South African in origin, and its toughness in poor soil, drought and coastal exposure is why it has become such a fixture of roadside and municipal planting in mild climates. That same toughness has a cost: in parts of Australia and New Zealand it seeds itself into bushland and is treated as an environmental weed, and sterile or low-seeding cultivars are recommended or required in some areas. Evergreen and deciduous types differ significantly in hardiness, the deciduous kinds generally standing more cold.

Growing notes

  • Tolerates coastal conditions well
  • Can become invasive in warm climates — check local rules
  • Flowers December–February in the Southern Hemisphere (midsummer) and June–August in the Northern — a reliable midsummer marker in either
  • Drought tolerant and salt tolerant — excellent for hot dry borders and coastal plantings
  • Cold-tender — needs frost protection or container culture in cooler climates
  • Deciduous hybrids (e.g. Headbourne hybrids) are significantly hardier than the evergreen species

Categories

Related plants

Cross-check Agapanthus against your zones

Reference

Agapanthus on Wikipedia