Scarlet monkeyflower is a herbacious perennial in the lopseed family. It is an attractive plant which bears red or orange-red flowers and toothed, downy leaves. It is native to the southwestern United States and Baja California. It is typically found in wetlands or moist areas. It can take full sun but seems to do better with part shade. It is sometimes used as a garden plant for its blooms, which attract hummingbirds. It is a fairly large, spreading, attractive plant which bears strongly reflexed, nectar-rich red or orange-red flowers and toothed, downy leaves. It is native to the West Coast and Southwestern United States and Baja California, and is generally found at low elevation in moist areas. Occasional populations of yellow-flowered Erythranthe cardinalis (which lack anthocyanin pigments in their corollas) are found in the wild.

Erythranthe cardinalis is cultivated in the horticulture trade and widely available as an ornamental plant for traditional gardens; natural landscape, native plant, and habitat gardens; and various types of municipal, commercial, and agency sustainable landscape projects. Cultivars come in a range of colors between yellow and red, including the "Santa Cruz Island Gold" variety, originally collected from Santa Cruz Island off the coast of California.