Quick Facts

• Mature size: Approx. 600–800mm high x 500–600mm wide

• Position: Full sun

• Foliage: Soft, ferny grey-green leaves

• Flowering: Late spring to autumn

• Flower colour: Rich red

• Climate tolerance: Heat and frost-tolerant

• Water needs: Low once established

• Maintenance: Low

Why You’ll Love It

Achillea ‘Cassis’ is a standout yarrow, loved for its deep, velvety red flower heads that age beautifully to softer, muted tones. Held on strong, upright stems above finely textured foliage, the blooms create bold colour blocks that work effortlessly in both naturalistic and contemporary plantings. Long-flowering and reliable, ‘Cassis’ brings structure, colour and pollinator activity to borders, meadow-style gardens and mixed perennial schemes, pairing beautifully with ornamental grasses and soft pastels.

Planting & Care Tips

• Plant in full sun for the strongest growth and richest colour

• Prefers well-drained soil; avoid heavy or waterlogged conditions

• Water during establishment, then sparingly once established

• Deadhead spent blooms to encourage repeat flowering

• Cut back flower stems and foliage in late summer or autumn to refresh the plant

• Divide clumps every few years to maintain vigour