Common Ragweed

Common name: Common Ragweed

Scientific name: Ambrosia artemisiifolia

Dimensions:
  Flower: About 1/4" (6 mm) wide
  Plant height: 1-5' (30-150 cm)

Blooming period: August-October

Habitat: Weedy places, roadsides, fields

Description: Elongated flower clusters of very small nodding green disk flower heads. Male heads upside down, stalked, in terminal clusters 1-6" (2.5-15 cm) long; female heads solitary or in small clusters in axils of bracts or small leaves at base of male clusters. Leaves 1 1/2-4" (3.5-10 cm) long, opposite below, alternate above, highly dissected, middle and lower leaves stalked, with blades narrowly to broadly oval or elliptic. Hay fever attributed to the fine pollen of this annual plant (and wrongly blamed on goldenrods). Aster family. (August 7)