Wormwood (_Artemisia absinthium_) is a hardy herbaceous Old World
perennial of the aster family, which has escaped from cultivation
in this country and now occurs as a weed in many localities in the
southern part of the United States. For many years it has been grown
commercially on a small scale, chiefly in Michigan and Wisconsin. The
dried leaves and tops have long been used medicinally, but the volatile
oil distilled from the plant now forms the principal marketable product.
Wormwood will grow in almost any soil, but the best results are to
be expected in deep, rich, moderately moist loams. The seeds are
frequently sown broadcast early in the fall, following a grain crop;
but if the plants are to be cultivated, it is best to start them from
seeds sown in seed beds early in the spring or from cuttings of the
young shoots taken in the spring and rooted in sand under glass or
in the shade of a lath shed. The seeds are very small and should be
sown on the surface of the soil in coldframes or seed beds and lightly
covered with very fine sandy soil. The plants are easily handled and
may be transplanted in moist weather with good results at almost any
time during the growing season. They are set about 18 inches apart in
rows 3 or 4 feet apart and are well cultivated. The soil should be kept
absolutely free from weeds, since their presence in the crop at harvest
time seriously damages the quality of the oil. A fair cutting of the
herb may be expected the first year after planting and full crops for
two or three successive, seasons, after which new plantings will be
found more satisfactory.
The plants are harvested when in full bloom and may be cut with a
scythe, or a reaper may be used if the area is large. While still
fresh, the plants are distilled with steam to obtain the volatile oil.
To prepare the leaves and flowering tops for market they are stripped
from the stems by hand after the plants are cut and carefully dried in
the shade without the use of artificial heat.
Experimental plantings have given yields at the rate of 2,000 pounds of
dry tops or 40 pounds of oil per acre. When grown on a commercial scale
the yield of oil appears to average about 20 pounds per acre.
The prewar price of the dry tops was about 6 or 7 cents a pound. Its
price in June, 1920, was 17 to 18 cents a pound. The oil was once used
extensively in the manufacture of absinth, but when the use of this
product was restricted in 1912 the demand for the oil fell off and the
price declined, until in the early part of 1915 it reached the low
level of $2 a pound. The price in June, 1920, was about $13 a pound.
The average annual production of oil of wormwood is about 2,000 pounds.
Owing to the limited use of this oil, there appears to be little room
for further profitable expansion of this industry.
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