Scientific NameAmaranthus spinosus
Other Common Names:
This summer annual can be found flowering from May through October.
The alternately arranged leaves occur on long petioles and are ovate in shape. The leaves grow from 1 1/4 to 2 1/2 inches in length. The erect branching stems can exceed 5 feet in height.
At the base of each leaf petiole are two 5 to 10 mm long spines, giving the Spiny Pigweed its name.
Flower Seed Head
The seedheads occur in clusters at the ends of stems arising from the leaf axils.
The seeds develop in a utricle 1 1/2 to 2 mm in length.
This plant prefers disturbed sandy loam soils, but can grow in a variety of conditions.
upright and nonwoody
Thorns or Spines
Approximate Flower Diameter
Dominant Flower Color
shorter than leaf
Stem Cross Section
round or oval