The whole plant has a characteristic fragrance—hence the name Sweet Clover—especially noticeable when in bloom and when the stems and leaves are cured into hay.
Geographical distribution: Sweet Clover is a native of the Old World where it occurs practically all over the temperate zone. It was probably introduced into America with the early settlers and is now spread all over the continent. It is common everywhere in Canada, especially in the eastern provinces.
Cultural conditions: Sweet Clover is generally found in waste places, along roads and railways, on river banks and in cultivated fields. It grows readily on almost any soil and will do well where practically nothing else will flourish. This ability to thrive almost anywhere, combined with its faculty of reseeding itself abundantly, is apt to give it the character of a troublesome weed where it is not desired. It does well in almost any climate and will live under very adverse conditions.
Agricultural value: When Sweet Clover is young it is succulent, but as soon as it flowers the stems get woody and lose their palatability. Its peculiar flavour is distasteful to stock, which will eat it only when nothing else is available. Milk and butter obtained from cows fed on green Sweet Clover have a peculiar taste disliked by most people. Furthermore, as the yield of hay is not high, Sweet Clover makes a poor forage plant. Its chief value is to enrich the soil and to improve its mechanical condition. Like other leguminous plants, the tubercles on its roots are filled with nitrogen-collecting bacteria. There seems to be conclusive evidence that these bacteria are identical with those of Alfalfa. At any rate, they act in exactly the same way and can therefore be used for the inoculation of Alfalfa fields. Six to eight pounds of seed are sufficient for an acre.
Seed: Sweet Clover seeds are common in commercial samples of Red Clover and Alfalfa and are sometimes found in Alsike. They are dull yellow and very like those of Trefoil, from which they may be distinguished by their larger size and a V-shaped light mark running from the scar.
There is no seed more prolific than that of ocimum; it is generally recommended to sow it with the utterance of curses and imprecations, the result being that it grows all the better for it; the earth too, is rammed down when it is sown, and prayers offered that the seed may never come up.—Pliny, Natural History, 23-79.