The number of drug plants which may be grown in the United States
is large, although the same plants are not equally adapted to the
conditions of soil and climate prevailing in different sections. Often
the most suitable plants for a particular locality can not be foretold,
especially in those situations where no attempts have yet been made to
grow them. In such cases it is well to select for cultivation plants
which thrive elsewhere under conditions most closely resembling those
of the new situation in which it is proposed to grow them. The success
with which ordinary field or garden crops can be grown will in general
indicate the possible suitability of a given location for growing many
medicinal plants. Since a number of native medicinal plants which
in their wild state are restricted to certain localities have been
successfully cultivated in situations far beyond their natural range,
there are good reasons for believing that many such plants will thrive
in sections where they are not now grown. However, good results can
scarcely be expected unless the plants are placed under conditions
similar to those in which they normally thrive.
In suitable soil and under favorable weather conditions the following
drug plants have been found to thrive well under cultivation in
numerous places in the Central and Eastern States and will probably
be found suitable for cultivation in many other situations if the
difference in climatic conditions is not too great:
Anise. Conium. Elecampane. Sage.
Belladonna. Coriander. Fennel. Stramonium.
Camomile. Digitalis. Henbane. Tansy.
Caraway. Dill. Horehound. Thyme.
Some perennials, such as belladonna and digitalis, are only partly
hardy and would be subject to winterkilling in the colder sections.
Such plants as aconite, arnica, lovage, poppy, seneca, valerian, and
wormwood seem to thrive best in the northern half of the United States
in situations where the rainfall is well distributed throughout the
growing season. On the other hand, cannabis, licorice, and wormseed
are better suited to the warmer climate of the southern half of the
United States. Aletris, althaea, angelica, calamus, orris, pinkroot,
peppermint, serpentaria, and spearmint are adapted generally for
situations in which the soil is rich and moist, but lavender and
larkspur are partial to well-drained sandy soil. Ginseng and goldenseal
occur naturally on rich soil in the partial shade of forest trees and
can be cultivated successfully only when planted in woodlands or in
specially prepared soil under artificial shade (fig. 1).