Culture
Best grown in lean, dry to medium, well-drained sandy loams in full sun. Plants do well in average garden soils and tolerate poor soils as long as drainage is good. Plants also tolerate hot, humid summers and drought. If grown ornamentally, plants are best sited in locations protected from strong winds. Plant stems tend to flop, particularly in hot, humid climates such as St. Louis and/or if grown in moist, rich soils. Consider cutting back plant stems in late spring before flowering to reduce overall plant height. Cutting plants back to lateral flower buds after initial flowering will tidy the planting and encourage additional bloom. Plants may also be cut back to basal foliage after bloom. Divide clumps as needed (every 2-3 years) to maintain vitality of the planting. Plants spread aggressively by rhizomes and self-seeding, and can naturalize into substantial colonies if left unchecked.
Noteworthy Characteristics
Achillea millefolium, commonly called common yarrow, is a rhizomatous, spreading, upright to mat-forming perennial that is considered by many to be an aggressive weed. Common yarrow from Europe and Asia was originally introduced to America in colonial times, and has since naturalized throughout the U. S. primarily along roadsides, fields, waste areas and lawns. These species plants are noted for producing deeply-dissected, fern-like, aromatic, medium green foliage and tiny, long-lasting, white flowers that appear in dense, flattened, compound corymbs (to 2-4” across) throughout the summer on stems typically rising 2-3’ tall. Foliage has a strong, somewhat spicy aroma that persists when used in dried arrangements. Species plants are uncommonly sold in commerce, however. It is the cultivars and hybrids of common yarrow, most of which have stronger stems, more upright habits and larger flowers, that have become popular flowering plants for ornamental gardens. Cultivars also extend the range of flower colors to include pinks, reds, creams, yellows and bicolor pastels.
The genus name Achillea refers to Achilles, hero of the Trojan Wars in Greek mythology, who used the plant medicinally to stop bleeding and to heal the wounds of his soldiers.
The specific epithet millefolium means "thousand-leaved" in reference to the highly dissected foliage.
Common yarrow has a large number of additional common names, including milfoil, thousandleaf, soldier’s woundwort, bloodwort, nose bleed, devil’s nettle, sanguinary, old-man’s-pepper and stenchgrass.
‘Pomegranate’ is a rhizomatous, spreading, upright yarrow that is noted for its bright magenta flowers, ferny aromatic foliage, compact size and vigorous growing habit. It is a naturally-occurring cultivar that was discovered in 2003 growing within a population of Achillea millefolium 'Summer Pastels'. Flowers appear in dense, flattened clusters (compound corymbs to 2-4” across) over a long summer bloom period on compact stems rising to 18-24” tall. Flower color holds well as flowers mature. Deeply-dissected, fern-like, aromatic, medium green leaves have a somewhat spicy aroma which may persist when used in dried arrangements. U.S. Plant Patent PP20,763 was issued on February 16, 2010. 'Pomegranate' is a member of the Tutti Frutti Series of yarrows that have been developed in The Netherlands. Other Tutti Frutti Series cultivars include 'Apricot Delight' (apricot flowers), 'Pineapple Mango' (yellow/salmon flowers), 'Pink Grapefruit' (rose flowers) and 'Wonderful Wampee' (pale pink flowers).
Problems
Stem rot, powdery mildew and rust are occasional disease problems. Plant stems are weak and lodge easily. If grown ornamentally, plants can develop into a tangled mass of stems and foliage by mid to late summer if not cut back. Strong summer rain storms with high winds can easily flatten exposed plantings. May spread somewhat aggressively.
‘Pomegranate’ has more compact stems and may be better able to deal with nasty summer weather than taller A. millefolium varieties.
Uses
Cottage gardens, seaside gardens, rock gardens, meadows, prairies and naturalized areas. Good fresh cut or dried flower.
Grows well in containers.