The flower stalks are weak and tend to flop. After flowering shear back the plants and they will form a dense mat of foliage. Plants are aggressive spreaders especially in moist rich soils.
very easy by division, cultivars may not come true from seed
The species plant Common Yarrow (Achillea millefolium) is native to Europe and Western Asia and considered to be a weed in many areas.
The species plants have been in cultivation prior to 1440 and used as a herbal remedy for many aliments. The Greek name honors Achilles a warrior of the Trojan wars.
I have grown many different varieties of Achillea millefolium. There seems to be a few secrets to successfully growing them. Avoid rich, moist, poorly drained soils and plant in a full sun site. They will tend to flop more in opposite conditions. Also cut back hard after the bloom fades.