Achillea ptarmica Diadem is a compact sneezewort yarrow with deep green lacy foliage and masses of double snow-white pompon flowers from summer into early fall. Its neat rounded habit grows about 30-45 cm tall and can spread 30-70 cm.
Plant in sun or partial shade and average, humus-rich, well-drained soil that retains modest moisture. Lightly prune faded flowers to encourage reblooming. The compact perennial suits containers, border fronts, ground cover, cutting gardens, and pollinator plantings.