Achillea millefolium

Native to Greenland and subarctic and temperate Eurasia, this aromatic perennial herb usually grows about 1 to 3 feet tall. Its finely divided foliage has a fern-like appearance and releases a strong scent when bruised. Flat-topped clusters contain many tiny flowerheads, each with central disc flowers surrounded by white or pink ray flowers. It spreads by seed and creeping underground stems that can form extensive colonies. Its flowers attract bees, butterflies, and other insects, and are used fresh or dried in flower arrangements. It has naturalized in New Zealand and southern and eastern Australia and is invasive in highland vegetation of the Australian Alps. Contact with the plant can cause dermatitis. Photographed in Colombia.