Achillea ageratifolia, the Balkan yarrow or Greek yarrow, is a species of flowering plant in the daisy family Asteraceae, native to Bulgaria and Greece. Growing to 20cm (10inches) tall and broad, it is a compact herbaceous perennial. It is a highly variable species, with three recognized subspecies. They have erect, simple, somewhat woody based stems.[1] The narrow grey-green foliage resembles that of a related genus Ageratum, hence the Latin specific epithet ageratifolia.[2] The solitary, daisy-like composite flower heads are white with yellow centres and about 2–3 cm across.[3] They appear May–July in the northern hemisphere.[4]
In cultivation in the UK, this plant has received the Royal Horticultural Society's Award of Garden Merit.[5] An adaptable plant, it prefers a sunny, open position. It is hardy down to -10 to -15 degrees C. It is also drought tolerant and grows well in USDA hardiness zones 3–8.[6] Common problems include aphids and downy mildew.[7]
It was first described in 1813 as Anthemis ageratifolia by James Edward Smith in Florae Graecae,[8] but was transferred to the genus Achillea by George Bentham & Joseph Hooker in 1873. The genus name refers to the Ancient Greek hero Achilles, who is said to have used yarrow leaves to stop his soldiers' wounds from bleeding.