Achillea ptarmica Diadem

Achillea ptarmica Diadem, commonly known as ‘Diadem Yarrow,’ is a resilient, compact perennial that's ideal for British gardens. Growing in a neat, rounded clump of about 30-35 cm, it’s cherished for its dense, finely textured foliage and its profusion of double, white, pompom-like blooms. 

This unique yarrow has a charming quality that sets it apart, with flowers that appear as delicate, clustered spheres rather than the flat blooms typical of other Achillea varieties.

Introduced by Dutch breeder Janus Verschoor, 'Diadem' is perfect for beds, borders, and even containers, adding structure and a soft, clean contrast to brighter summer blooms. It’s especially suited to the UK climate, thriving through both sun and partial shade and showing excellent winter hardiness.

Regular pruning will reward gardeners with prolonged flowering throughout the season, making it a reliable and low-maintenance choice for those looking to add texture and understated elegance to their garden spaces.

Botanical name: Achillea ptarmica Diadem
Common names: Yarrow, Sneezewort, Bastard Pellitory, European Pellitory, Fair-maid-of-France, Goose Tongue, Sneezeweed, Wild Pellitory, White Tansy
Flower colour: White
Flower Size: 1cm
Plant size: 1
Blooms: July-September
Soil: Moist
Sunlight: Full sun
Established height: 35cm
Established spread: 35cm
Life cycle: Perennial
Hardiness: Fully hardy
Years to establish: 2-3 years
Plant spacing: 5 per m2
Easy to grow
Scented: No
Attracts Wildlife: Butterflies, Bees, Birds, Pollinators
Pruning instructions: Remove the faded flower stalks
Pruning recommended once a year
Pruning time :July to September
Disease resistance: Very good
Overwinter: Can be left in the ground
Dispatch: Early Spring (Mid March/April)