Two broods: late May to June; and August.

Open, weedy areas, meadows, and prairies.

Wing span: ⅞″ to 1⅜″

The upper side of the female is brown with light blue scales and a white margin. There is a submarginal row of reddish-orange spots on both the hindwing and the forewing.

Various legumes of the pea family including Canadian milkvetch (Astragalus canadensis var. canadensis), Cooper’s milkvetch (Astragalus neglectus), ground plum (Astragalus crassicarpus var. crassicarpus), wild licorice (Glycyrrhiza lepidota), bird’s-foot trefoil (Lotus corniculatus var. corniculatus), alfalfa (Medicago sativa ssp. sativa), black medick (Medicago lupulina), and, rarely, sundial lupine (Lupinus perennis var. perennis) and bigleaf lupine (Lupinus polyphyllus ssp. polyphyllus).

Caterpillars eat young leaves and are tended by ants who feed on the caterpillars’ sugary secretions.

Karner blue (Plebejus melissa samuelis) female has no submarginal spots on the upper side of the forewing.

Northern blue (Plebejus idas) female has less blue on the upper side.

Also called Orange-Bordered Blue.