Achillea ageratifolia
Introduction '''''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  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. The narrow grey-green foliage resembles that of a related genus ''Ageratum'', hence the Latin specific epithet ''ageratifolia''. The solitary, daisy-like composite flower heads are white with yellow centres and about 2–3 cm across. They appear May–July in the northern hemisphere.
Cultivation In cultivation in the UK, this plant has received the Royal Horticultural Society’s Award of Garden Merit. 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.Common problems include aphids and downy mildew.
Taxonomy It was first described in 1813 as ''Anthemis ageratifolia'' by James Edward Smith in Florae Graecae, 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.
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