While sweet clover is to be found growing in many countries and on all
the continents of the world, it is native to temperate Europe and Asia
as far east as Tibet. It is grown to a limited extent in England,
while in the eastern part of Scotland a small quantity is considered
valuable in hay on account of its agreeable odor. The famous Cruyere
cheese of Switzerland owes its flavor to yellow sweet clover. In
Germany it has given very good results when used as a green-manure,
while in parts of Russian Poland and Austria-Hungary it is grown as
a green-manure, pasturage, and hay crop on poor soils. This plant is
used for forage and as a soil-improving crop in the central provinces
of India, while sour clover, commonly referred to as _Melilotus
parviflora_, is credited with furnishing 75 per cent of the feed for
the cattle of King Island, Tasmania, which produce the best beef and
butter sold on the Tasmania market.
[Illustration: Fig. 6.--Outline map of the United States, showing the
localities where sweet clover is grown for forage or for green-manure.
Each dot or circle indicates a county where 50 acres or more is grown
under cultivation. The solid dots represent white or yellow sweet
clover; the circles represent annual yellow sweet clover.]
At the present time sweet clover is grown rather extensively as a field
crop in the limestone regions of Alabama, Mississippi, and Kentucky,
in northern Illinois, and throughout the western North-Central and
Mountain States (fig. 6): in fact, it is grown as a cultivated crop to
some extent in nearly every State in the Union. Comparatively little
sweet-clover seed is sown in the Atlantic Coast States, since there
the soils are for the most part acid, and heavy applications of lime
will be necessary before sweet clover can be grown successfully. It
is questionable whether this plant will ever be of much importance in
the South Atlantic States, as cowpeas, soy beans, and crimson clover
will make a fair growth on those soils in their present condition.
The acreage of sweet clover probably will increase in the New
England States, where it should prove of value as pasturage and as a
soil-improving crop on soils where red clover no longer can be grown.
Sweet clover grows abundantly in the limestone regions of northwestern
New York.
A much larger acreage of sweet clover is grown in northern Illinois
than in any other of the eastern North-Central States. The conditions
in the western North-Central States and in the Mountain States appear
to be particularly adapted to this crop. It is in that part of the
country that the largest acreage is found, and, with the exception
of the limestone regions of the South, that the least difficulty is
experienced in obtaining a stand.
In those parts of the Mountain and Pacific Coast States, especially
Utah, where it has not been tested carefully or where red clover or
alfalfa can be grown successfully, sweet clover is looked upon as a
weed. It may rightly be considered a weed in the irrigated regions of
the West and Northwest, where it grows luxuriantly on ditch Banks.
The dissemination of this plant in all parts of the country has been
hastened by beekeepers who have seeded it in waste places for the
production of honey.