Botanical name: Parthenium hysterophorus Family: Asteraceae (Sunflower family)
Carrot Grass is native to the subtropics of North and South America. It is a fast-maturing annual (or, under certain conditions, a short-lived perennial) with a deep tap root and an erect stem that becomes woody with age. It may eventually reach a height of 2 m. Its leaves are pale green, branched and covered with soft fine hairs. The small white flowers (4 mm across) have five distinct corners and grow on the stem tips. Each flower produces 4-5 black wedgeshaped seeds that are 2 mm long with thin white scales. It is considered a highly invasive weed. Its large and persistent soil seedbank, fast germination rate and ability to undergo dormancy make it well adapted to semi-arid environments. It also releases chemicals that inhibit the germination and growth of pasture grasses and other plants.
The flower labeled Carrot Grass is ...