Table 4. Pigweed identification characteristics.

Species

Hairs

Leaves

Flowers

Seed Head

Redroot

Small, fine

Rounded

Monoecious

Highly branched, compact

         

Smooth

Small, fine

Rounded

Monoecious

Highly branched, < compact

         

Waterhemp

       

Tall

None

Lanceolate

Dioecious

Top of plant and at leaf tips

Common

None

Lanceolate

Dioecious

 
         

Palmer Amaranth

Few to none

Poinsettia-like, "V" variegation

Dioecious

Nonbranched, 1 to 2 feet long

         

Powell Amaranth

Small, fine

Tapered and slightly pinched at end

Monoecious

Branched, < RR or smooth, 4 to 8 inches long

         

Spiny Amaranth

None

"V" variegation, spines at nodes

Monoecious

Male toward top; female toward bottom

         

Tumble

?

Egg-shaped, wavy edges, olive green

Monoecious

No distinct flowering structure, flowers at nodes

         

Prostrate

?

Spatulate, cotyledons longer than others

Monoecious

No distinct flowering structure, flowers at nodes

NOTE: Each of these species may have a reddish-colored root.

Redroot vs. smooth: Differentiate only when seed head is present.

Redroot/smooth vs. waterhemp: Differentiate by hairs, leaf shape, waxy leaves of waterhemp.

Tall vs. common waterhemp: Differentiate by fracture of seed capsule (utricle): common = two sections, tall = irregular.