Sweetclover species in Texas
White flower types (Melilotus alba Desr.) currently (2008) grown in Texas are generally annuals and are probably derived from Hubam.
Yellow flower types currently (2008) grown in Texas belong to two different species:
1. small, annual yellow flower sweetclovers (alternate name – Sour Clover); (Melilotus indica [L.] All.) — These plants get about 12 to 18 in tall and flower in March. They can be seen on roadsides in central Texas. No commercial seed are available.
2. biennial yellow flower types (Melilotus officinalis [L.] Lam.) like the cultivar Madrid. This species is slightly smaller than Hubam but does not flower in the establishment year. Generally considered not as reliable as the annual, white flower (Hubam) types. Research is in progress with annual, yellow flower M. officinalis experimental lines.
Diagram from Bulletin 791: Sweetclover in Texas, 1955, R.C. Potts.
Texas Agricultural Experiment Station