redroot amaranth
Family
AmaranthaceaeScientific Name
Amaranthus retroflexus
Other Common Names:
careless weed
rough pigweed
redroot pigweed
Habit
This erect summer annual can be found flowering from July through October.
Leaves
The alternate leaves are ovate with wavy margins. The leaves are hairy on the lower surface, along the prominent veins. The stout, hairy stem can grow up to 6 1/2 feet in height.
Identifying Characteristics
This plant can be distinguished from other pigweeds by its less dense terminal spike. The first true leaves of this plant are alternate, unlike any of the other pigweeds.
Flower Seed Head
The small greenish flowers occur in terminal spikes. Smaller spikes of flowers may be found at the leaf axils.
Seed Fruit
The glossy black seeds each form inside a 2 mm long utricle that splits open at maturity.
Where Found
This plant can be found in pastures, along roadsides, and other disturbed soils.
Growth Habit
upright and nonwoody
Thorns or Spines
not present
Approximate Flower Diameter
pencil
Dominant Flower Color
green
Leaf Hairs
Varies:
has hairs,
no hairs
Leaf Shape
spatulate
Leaf Arrangement
alternate
Leaf Margin
wavy
Leaf Structure
simple
Leaf Stalk
longer than leaf
Stem Hairs
has hairs
Stem Cross Section
round or oval
Milky Sap
not present
Root Structure
Varies:
fibrous,
taproot
Life Cycle
summer annual
Ochrea
not present
Plant Type
Herb