Source: Magness et al. 1971 In general, the white-flowered forms of sweet clover are somewhat ranker growing, heavier yielding, and have coarser stems than the yellow-flowered. They are later maturing so are generally preferred for pastures in areas of ample moisture. The more vigorous growth and heavier yields make them somewhat superior for soil improvement. In growth habit and appearance the two are similar except for flower color. Most of the M. alba grown is so-called common white. Two selected varieties in addition to common are in the trade. Spanish is leafier and somewhat more productive than common and is recommended for higher rainfall grain areas of the Pacific Northwest, as well as the Great Plains. Evergreen is late maturing, providing long grazing and heavy forage yields. It is generally adapted in the Corn Belt. Penta is a low-coumarin variety, bred in Wisconsin. Annual forms of M. alba are also in the trade. Hubam, Floranna, and Israel are such kinds. They are most useful in the central and southern regions where the growing season is relatively long.