Scientific NameAmbrosia trifida
Other Common Names:
This erect summer annual flowers from July through September.
The opposite leaves are palmately lobed with 3 lobes, although it may occasionally have 5, or be simple. Each lobe is lanceolate shaped, and have toothed margins. The lower leaves are more deeply lobed, while the upper leaves tend to be simple. Both the leaves and the stem are rough and hairy
This plant can be differentiated by it's opposite leaves, and its crown shaped achene.
Flower Seed Head
The small greenish flowers occur in long racemes, and are divided by male and female flowers. The male flowers occur on the ends of long racemes, while female flowers are found at the base of the racemes, and at the leaf axils.
Each seed is enclosed in a 6 to 12 mm long black achene. The achene is crown shaped, with a long central spike surrounded by 5 shorter points.
This plant prefers moist soils in full sun or light shade. It can be found growing in ditches, low lying fields, and other areas that tend to collect water. In dry conditions, or in poor soils, the plant will be smaller and somewhat wilted.
upright and nonwoody
Thorns or Spines
Approximate Flower Diameter
Dominant Flower Color
shorter than leaf
Stem Cross Section
round or oval