Singer Billie Jo Spears, whose performance of “Blanket on the Ground” went No. 1 on the country charts in 1975, died of cancer on Wednesday, Dec. 14, in Vidor, Texas. She was 73.No cause of death was stated. The Beaumont native performed as a 13-year-old on the Louisiana Hayride radio program out of Shreveport, La., considered a stepping stone to Nashville’s Grand Ole Opry at the time. She worked as a secretary until her music career took off and left Texas for Nashville in the mid-1960s. She had trouble with her vocal cords in the early 1970s but scored her chart-topper in 1975 and was voted most promising female vocalist by the Academy of Country Music in 1976. Her other hits included “Mr. Walker, It’s All Over in 1969; “What I’ve Got in Mind’ in 1976; “Misty Blue” in 1976; and “If You Want Me” in 1977. Spears recorded duets with country singer Del Reeves and performed at the prestigious Wembley Festival in England a few times in the 1970s, cementing her following in the U.K. before her recording career tailed off in the mid-1980s.