Common milkweed sightings surge as monarch season peaks
iNaturalist Community
Native Plants
The tall, pink-flowered weed you might have yanked from a garden bed is the only plant monarch caterpillars can eat, so leaving it standing directly helps a butterfly population that's been sliding for years.
Right now, hundreds of people across the country are photographing and logging common milkweed sightings on the nature app iNaturalist. It's not random: this is the plant's peak bloom time, and it's also exactly when monarch butterflies need it most to lay their eggs. If you spot clusters of pink, ball-shaped flowers and wide oval leaves in a field or roadside ditch this week, you're probably looking at it.
Key Findings
405 research-grade observations of Asclepias syriaca were logged in a single week
The species ranked among the most-observed plants on iNaturalist this week, indicating broad geographic and observer participation
Timing coincides with peak summer bloom, which overlaps with monarch butterfly egg-laying season
chevron_right Technical Summary
Common milkweed is having a big observation week on iNaturalist, with 405 research-grade sightings logged by citizen scientists across its range. That surge tracks with peak summer bloom and the plant's critical role as the sole host for monarch butterfly caterpillars.
Abstract Preview
Original paper
Trending: common milkweed (Asclepias syriaca) — 405 observations this week
common milkweed is among the most observed plant species this week with 405 research-grade observations.
open_in_new Read full abstractAbstract copyright held by the original publisher.
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Asclepias syriaca, commonly called common milkweed, butterfly flower, silkweed, silky swallow-wort, and Virginia silkweed, is a species of flowering plant. It is native to southern Canada and much of the United States east of the Rocky Mountains, excluding the drier parts of the prairies. It is i...