[2][5] In 2018, a disjunct population was discovered in the Thousand Islands region of Ontario, Canada.

[6][7][1] This cactus grows in a wide variety of habitat types, including sagebrush, Ponderosa pine forest, prairie, savanna, shrublands, shrubsteppe, chaparral, pinyon-juniper woodland, and scrub.

[8] The flowers are 2.5 to 4 cm (1 to 1+5⁄8 in) long and may be yellow, magenta,[5] or red in color (tending to turn pink or orange with age).

It provides over half the winter food for the black-tailed prairie dog in one area.

Ranchers intentionally burn stands of the plant to make it palatable for livestock when little other food is available.

[3] O. polyacantha provided the Lewis and Clark Expedition with opportunity for admiration and more often complaint about the plant.