Prostrate Pigweed Amaranthus albus
Prostrate Pigweed is an introduced annual herb, found in Alaska and the lower 48 states. It grows to 0.9 ft and blooms May – Oct.
More about this plant
Amaranthus albus is an annual species of flowering plant native to the Americas. Its common names include common tumbleweed, tumble pigweed, tumbleweed, prostrate pigweed, pigweed amaranth, white amaranth and white pigweed. Wikipedia →
Prostrate Pigweed is flagged invasive in the U.S. These natives fill a similar niche — same growth habit, bloom season, height, and region — so you keep the look and feed local wildlife instead of spreading a problem.
Growing & care
USDA PLANTS · TRY- Hardiness
- ≥ zone 4 derived from its U.S. range
- Height
- 0.9 ft
- Lifespan
- Annual
- Foliage
- Broadleaf
- Flower colour
- Green AI AI image-analysis of community-science photos (~87% expert agreement) — not a botanical record
Wildlife & pollinators
How pollinator value is scored →❧ Caterpillar hosts ~29 caterpillar species
Amaranthus supports ~29 caterpillar species.
Native butterfly & moth caterpillars are the base of the terrestrial food web — most songbirds rear their young almost entirely on them. As a host for native Lepidoptera this is a moderate genus.
Recorded feeding on Amaranthus in North America, including:
+ 8 more species → ↑ show fewer
Wildlife & visitors 57 birds · 1 nectaring
Open records of who else uses Prostrate Pigweed — a generalist food-web signal, kept separate from the keystone Ecological Value.
Recorded eaten by 57 birds species (fruit, seed, browse) — the most-recorded:
1 adult butterfly & moth species is recorded nectaring at its flowers:
Related plants
More Amaranthus →
How we know this (3) Methods & honest limits
A recorded categorical fact: each species is tagged C3 (standard), C4 (heat/water-efficient) or CAM (succulent, night-time CO₂ uptake) — or a facultative combination. We only show a trait card for the noteworthy C4/CAM cases; C3 is the unremarkable majority, kept in the data but not surfaced as a card.
We take the plant’s U.S. county range and look up each county’s long-term climate, then summarise: native rainfall = the median annual rainfall across its counties; heat tolerance = the warm end (90th percentile) of average temperature across its range (mirroring how our cold-hardiness floor uses an extreme). Counties + medians blunt the roadside/observer bias that makes point-level climate unreliable. Needs at least five placeable counties.
Honest limits: A realized, sampling-biased niche (where it has been recorded, not its physiological optimum), and county climate is coarse — large Western counties span deserts and mountains. Derived guide, never a measured fact.
McKenzie et al. assigned each species a flower colour with a GPT-4V vision model over iNaturalist photos. We use the confident tier plus a separately-labelled lower-confidence top-up (mostly inconspicuous green/brown flowers), and render it as a small tint — never as an asserted fact, and kept out of the written synopsis.
Honest limits: AI image inference (~87% expert agreement on the confident tier); a decorative, confidence-tiered indicator, not a measured trait.
Sources for this entry (23) Open & cited
Cite this page Open data, please attribute
PlantKey’s data is open under CC BY-SA 4.0 — free to reuse and adapt, with attribution and the same licence. Photos keep their own per-image licence + credit (see Sources above).
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