Yarrow is a hairy, aromatic perennial with a simple or branching stem. Flowerheads are minute, in dense, flat-topped, terminal clusters. Ray florets are minute, white, rarely light pink; the disk florets are light yellow. Blooms May–November. The leaves are finely dissected, fernlike, to 10 inches long, narrow-oblong, alternate. The odor is distinctively sweet and rather soapy, akin to the smell of chrysanthemums.
Several cultivars have been developed for the gardener, with a variety of flower colors.