Ragweed Parthenium

Parthenium hysterophorus L.

Asteraceae (Aster Family)

▲ seedling

▲▼ flowering plants

 

▲ flowers

Ragweed Parthenium:

·         annual growing 12-48” tall with dark-gray-green divided leaves and small white flowers

·         leaves look like common ragweed leaves

·         inflorescences form rounded to flat-topped, open cluster at top of plant

·         produces abundant pollen that can aggravate allergies in allergic individuals

·         found in dry to moderately moist soils of various fertility

·         has shown herbicide resistance and invasive nature in other countries

·         occasional weed in southwest Missouri (not common)