Palmer Amaranth
Description
- Palmer amaranth is a summer annual that commonly reaches heights of 6- 8 feet but can reach 10 feet or more.
- The green leaves are smooth and arranged in an alternate pattern that grows symmetrically around the stem. The leaves are oval to diamond-shaped. There is a small, sharp spine at the leaf tip.
- The leaves of some Palmer amaranth plants have a whitish V-shaped mark on them. Not all Palmer amaranth plants display this characteristic.
- There are separate male and female plants.
- Palmer amaranth looks similar to our native pigweeds such as tall waterhemp (A. tuberculatus), redroot and smooth pigweeds (A. retroflexus and A. hybridus respectively). Here are some distinguishing characteristics:
- Redroot and smooth pigweeds have fine hairs on their stems and leaves. Palmer amaranth and waterhemp do not have these hairs.
- The petiole (stalk connecting a leaf to the stem) is longer than the length of the leaf. For tall waterhemp, the petiole will be only half the length of the leaf.
- Seedhead spikes on female Palmer amaranth plants are much taller (up to 3 feet long) and more prickly than waterhemp or redroot and smooth pigweed spikes.
Habitat
Palmer amaranth is adapted to the arid habitat of the desert southwest. Outside of its native range, Palmer amaranth has been documented in annual row crop fields and disturbed, sunny areas.