[2][3] It is native to southern Canada and much of the United States east of the Rocky Mountains, excluding the drier parts of the prairies.

The highly fragrant, nectariferous flowers vary from white (rarely) through pinkish and purplish and occur in umbellate cymes.

[8] More than 450 insect species feed on A. syriaca, including flies, beetles, ants, bees, wasps, and butterflies.

[12] The development and widely adopted cultivation of herbicide-resistant staple crops such as corn and soybeans have led to a massive reduction in weeds and native plants such as milkweeds.

In 2018, the chief executive officer (CEO) of the National Wildlife Federation stated that the monarch butterfly population had decreased by 90 percent during the previous 20 years and cited the reduction in milkweed as a contributing factor.

[15] Despite this, deforestation due to human settlement may have expanded the range and density of common milkweed in some regions.

[16] Common milkweed has even become invasive as it is naturalized in several areas outside of its original native range, including Oregon and some parts of Europe.

[23] Efforts to restore falling monarch butterfly populations by establishing butterfly gardens and monarch migratory "waystations" require particular attention to the target species' food preferences and population cycles, as well to the conditions needed to propagate and maintain their food plants.

[24] In the northeastern United States, monarch reproduction peaks in late summer when most of the plant's leaves are old and tough.

[32] Euell Gibbons, the author of Stalking the Wild Asparagus (1962), wrote that milkweed is bitter and toxic.

Gibbons devised a method to remove the bitterness and toxicity by plunging the young shoots into boiling water and cooking for one minute, repeating the procedure at least three times to make the plant safe to eat.

U. S. Department of Agriculture studies in the 1890s and 1940s found that common milkweed has more potential for commercial processing than any other indigenous bast fiber plant, with estimated yields as high as hemp and quality as good as flax.

[16] Genomic analysis of several hundred different A. syriaca plants from throughout the species natural range in eastern North America showed that this species is a single panmictic population that experienced expansions about 12,000 years ago, after the recession of North American glaciers, and more recently, about 200 years ago, during clearing of forests for agriculture in the eastern United States.