Country singer Wilma Lee Cooper, whose tradition-based down-home style left a mark on bluegrass music, died Sept. 13 of natural causes in Sweetwater, Tenn. She was 90.

Born Wilma Leigh Leary in Valley Head, West Virginia, Cooper sang with her family’s gospel group the Leary Family in the ’30s and ’40s. She married the unit’s fiddler Dale T. “Stoney” Cooper in 1941.

The Coopers broke through in 1947 when they appeared on radio’s popular WWVA Jamboree in Wheeling, West Virginia. They cut their first records the same year for the small Tennessee label Rich-R-Tone, which also released the first singles by bluegrass pioneers the Stanley Brothers. They were signed to Columbia from 1949-53, without success.

The duo recorded with their band the Clinch Mountain Clan for the Hickory label in the ’50s and ’60s. Their biggest hits included “Big Midnight Special,” a country arrangement of Lead Belly’s “Midnight Special” (No. 4, 1959), a cover of countrypolitan singer-songwriter Don Gibson’s “There’s a Big Wheel” (No. 3, 1959) and a reading of the standard “Wreck On the Highway” (No. 8, 1961).

The Coopers later briefly recorded for Decca and Starday. They joined Nashville’s Grand Ole Opry in 1957, and performed on the popular WSM broadcast until Stoney Cooper’s death in 1977. Wilma Lee later recorded as a soloist for the independent roots labels Rounder and Rebel. She retired after suffering a stroke in 2001.

She is survived by her daughter Carol Lee, an Opry performer. (Christopher Morris)