Erigeron bonariensis

Stiff hairs cover the plant.

Basal rosette leaves, before plant matures and flowers, Maui, Hawaii

Foliage becomes grey-green in dry-summer regions, such as Israel

White ray flowers and yellow disc flowers in fully "open" flower heads, Maui, Hawaii

Flower heads are followed by seeds, which are easily carried by the wind.

Common names of E. bonariensis include flax-leaf fleabane, wavy-leaf fleabane, Argentine fleabane, hairy horseweed, asthma weed and hairy fleabane.[2]

Erigeron bonariensis grows up to 75 cm (29.5 in) in height and its leaves are covered with stiff hairs, including long hairs near the apex of the bracts. Its flower heads have white ray florets and yellow disc florets. It can easily be confused with Erigeron canadensis, which grows taller, and E. sumatrensis.[3]

It flowers in August and continues fruiting until the first frosts. It is instantly recognisable by its blue-green foliage, very narrow, undulate stem-leaves, and purple-tipped involucral bracts. It reproduces only by seed, which are easily blown and spread by wind.

Erigeron bonariensis is found throughout the tropics and subtropics as a pioneer plant; its precise origin is unknown, but most likely it stems from Central America or South America. It has become naturalized in many other regions, including North America, Europe and Australia.[4][5][6][7]

E. bonariensis is a rare alien in southeastern England, found along walls and in cracks in pavements and concrete driveways. It is widespread throughout Australia, where it thrives on roadsides, fallows, pastures, gardens, lawns, footpaths, parks, riparian vegetation, forest and wetland perimeters, waste dumps and disturbed grounds.[8][9]