Fauna
Plant

Palmer's Amaranth

Amaranthus palmeri

Also known as Carelessweed, Dioecious Amaranth, Palmer Amaranth, Palmer's Pigweed

Palmer amaranth is a fast-growing dioecious annual herb capable of shooting upward by several centimeters a day under direct summer sunlight. Female plants produce elongated flowering spikes packed with stiff, prickly bracts and can shed up to half a million tiny black seeds in a single season. Highly adaptable across riparian washes and disturbed agricultural soils, it has evolved widespread resistance to common herbicides, transforming it from a regional native into a formidable agricultural competitor.

AnnualFast-GrowingWind-Pollinated
Palmer's Amaranth reference1 / 7
(c) Douglas Goldman, some rights reserved (CC BY-SA), uploaded by Douglas Goldman · cc-by-sa
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Least ConcernConservation statusIUCN Red List categoriesLCNTVUENCREWEXLeast ConcernRed List categories, explained →
Key facts
Diet & preyAutotrophic (photosynthesis)
Predators
  • Pigweed flea beetle (Disonycha glabrata)
  • Mourning dove (Zenaida macroura)
  • Granivorous ground beetles
ThreatsHerbicide applications, mechanical tillage, crop competition, and seed predation
HabitatsAgricultural fields, roadsides, disturbed soils, riverbanks, and arid washes
Life spanAnnual (4–8 months)
Classification
  1. OrderCaryophyllales
  2. FamilyAmaranthaceae
  3. GenusAmaranthus
  4. SpeciesAmaranthus palmeri
Range & activity
Range data is not available yet.
Safe observation
Interaction riskHigh
  1. Low
  2. Moderate
  3. High
  4. Very high
Why interaction risk is high
Safe to observe at a normal distance.
Responsible observation
  • Petiole Check: Bend a mature leaf back toward the stem; if the leaf stalk is distinctly longer than the blade, it points to Palmer amaranth.
  • Spike Examination: Look at the terminal flowering spike to tell soft pollen-bearing males from stiff, prickly female seed-heads.
  • Equipment Hygiene: Clean mud and debris from boots and gear after walking near infestations to avoid transporting the minute seeds.
Related species
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