Argemone polyanthemos aka Plains Prickly Poppy

Argemone polyanthemos is known as prickly poppy. It belongs to the poppy family, Papaveraceae. This annual or biennial grows in temperate parts of the United States. Its native range spans the central and west-central states. It extends from Texas and New Mexico to Wyoming and South Dakota. Wild plants grow on plains, slopes, foothills, and roadsides. They occur in both sandy and grassy ground. The species has also spread beyond its original range. Some of these sites lie west of the Rocky Mountains.

Plants form a deep taproot and grow about 3 feet [0.91 metres] tall. Less often, they reach 4 feet [1.22 metres]. Their spread can reach 2 feet [0.61 metres]. Pale blue-green leaves and stems give the plant its color. The lobed leaves reach about 0.67 feet [0.20 metres] long. Prickles occur on the plant, but the upper leaf surfaces lack them. This species has fewer prickles than many other members of its genus. It is a herbaceous plant rather than a woody shrub.

White flowers have yellow stamens at their centers. Each bloom measures about 0.25–0.33 feet [0.08–0.10 metres] across. The listed flowering season runs from June through August. These large blooms provide the main display in garden beds. The plant also suits borders grown with annual flowers. Plants may set seed and produce new seedlings in the garden. Its annual or biennial life cycle means individual plants are short-lived.

Grow prickly poppy in full sun and well-drained soil. Average soil with dry to medium moisture suits it. It also grows well in poor sandy or gravelly ground. Sow fresh seed outdoors each year, just before the last spring frost. Its dislike of transplanting makes direct sowing a useful choice. Starting plants indoors in pots can prove difficult. Missouri Botanical Garden lists it for USDA zones 2–11. That broad range accompanies its use as a garden annual.

Routine care needs are low, but seed starting presents some limits. No major insect or disease problems are reported. Downy mildew, anthracnose, and root rot can still occur. The supplied evidence gives no species-level food or toxicity guidance. It therefore does not establish that any part is safe to eat.