From Wikipedia :
"The title, "Crimson and Clover", was decided before a song had been written for it. The combination of unknown meaning came to James as he was waking up, comprising his favorite color – crimson – and his favorite flower – clover. (There is also a species of clover native to Europe called the crimson clover.) A song to fit the phrase was written by Tommy James and bassist Mike Vale, but was scrapped. His following collaboration with drummer Peter Lucia, Jr. was more successful (Lucia has said that he himself came up with the Crimson and Clover phrase while watching a high school football game between his hometown Morristown (NJ) Crimson and Hopatcong (green, or "clover")).