The name millefolium means “a thousand leaves,” referring to its finely divided foliage. It spreads by rhizomes and can form dense colonies, making it a resilient groundcover. It can, however, become aggressive under certain conditions but remains well-behaved in others. It tends to spread vigorously in open, disturbed soils with full sun and moderate moisture, where its rhizomatous roots and prolific self-seeding allow it to form dense mats that crowd out more delicate species. In these settings—such as roadsides, early-stage restorations, or unmonitored garden beds—yarrow can quickly dominate. However, in lean, dry soils or densely planted prairies with strong competition, its growth is often more restrained. It also behaves more modestly in shaded microclimates or when managed through regular thinning and deadheading. Ultimately, yarrow’s behavior is shaped by context: it can be a valuable stabilizer and pollinator plant when thoughtfully placed, or a persistent spreader when left unchecked. Yarrow blooms from late spring through early fall and attracts pollinators such as bees, butterflies, and other beneficial insects. Its aromatic leaves have been used in teas and poultices, and it was once widely employed in traditional herbal medicine for treating wounds and fevers. The plant is resistant to deer, tolerant of drought, and thrives in poor soil and full sun—making it a great choice for low-maintenance and native landscaping. (July)