Parthenium integrifolium aka Wild Quinine

Parthenium integrifolium is a perennial in the aster family. Common names include wild quinine and American feverfew. It comes from the central and eastern United States. It grows in prairies, glades, rocky woods, and old fields. It also occurs along roadsides and at woodland edges. Its native range includes areas with a temperate climate.

The plant forms upright clumps with a basal leaf rosette. Garden heights vary from 2–5 feet [0.6–1.5 metres]. Chicago Botanic Garden describes shorter plants, while RHS gives the upper range. Clumps can spread to about 1.6 feet [0.5 metres]. Large, oval green leaves grow at the base. They feel thick, rough, and leathery, and have toothed edges. Basal leaves have long stalks and more rounded teeth. Upper leaves attach straight to stems and have sharper teeth. Short hairs lie close against the leaves and stems. The leaves have a scent, and some foliage may persist.

Stout, branched stems hold tight groups of small white flower heads. Each head has tiny rays, and the flowers have a faint scent. Bloom starts in May and lasts through summer. North Carolina State Extension reports flowers into September. Chicago lists a bloom period that can reach October. Bees visit for nectar, while beetles feed on pollen. The plant also draws butterflies and birds. Seedheads can remain in place to add form in winter. Remove spent heads when seed is not needed.

Full sun gives the best growth, though RHS also allows partial shade. The plant accepts clay, loam, sand, and chalk soils. It tolerates acid, neutral, and alkaline conditions. Moist soil with good drainage suits garden growth. It also copes with dry soil, drought, and shallow rocky ground. Sources place it in USDA zones 4–8 and UK rating H7. It needs little upkeep and has few serious pest or disease problems. RHS gives two to five years to reach full size.

Use it in native beds, cottage gardens, meadows, or prairie plantings. Its flowers suit both fresh and dried arrangements. Chicago reports resistance to deer. PFAF lists no known food use and warns of skin reactions or allergies. It records past medicinal uses of leaves, roots, and flowering tops. These include leaf poultices for burns and treatments for fever. Such records do not establish safe use as a home remedy.