Achillea ptarmica

The Achillea ptarmica 'Diadem' is a highly floriferous and neatly shaped variety of double-flowered sneezewort. Adorned with white pompom-like flowers, this perennial forms a round and dense tuft that appears covered in snowflakes. Unlike many other achilleas, it prefers moderately moist soils. Very hardy and charming, it thrives in sun or partial shade, at the front of flower beds, in borders, on balconies and terraces.

The Achillea ptarmica 'Diadem' 'Versdidem' is a deciduous perennial herbaceous plant belonging to the Asteraceae family with a slightly creeping rhizomatous root system. Its above-ground growth emerges in spring, dries up, and disappears in autumn. Its ancestors, sometimes called sneezewort, marsh yarrow, sneezeweed, or stonebreaker, is a species widespread in northern Europe and Asia. Its natural habitat consists of meadows and wet areas. This hybrid variety 'Diadem' has a bushy, compact and dense habit, forming a tuft about 30-35 cm (12-14in) tall and wide. The stems bear slender, lanceolate, dark green leaves. Flowering occurs from July to September if faded flowers are regularly removed. At the tips of the stems, numerous double pure white flowers, about 1 cm (1in) in diameter, with a barely touched yellow centre, appear. This flowering is popular with bees and butterflies.

The Achillea ptarmica 'Diadem' is highly cold-tolerant (-20°C) and makes a lovely companion for other border perennials and annuals that bloom on terraces. For example, pair it with the false wallflower Zwerg Jaune, the perennial wallflower Poem Lavender, or the fragrant dwarf alyssum in the Magic Circles mix. Aphids often attack sneezewort to the point that it is known in organic gardening to prevent or avoid other plants from being invaded. It is ideal in herb gardens, flower beds, meadows, and cut flowers. Its association with scabious and phlox is also very successful.