Digitalis, or foxglove (_Digitalis purpurea_), is a fairly hardy
European perennial, which has long been grown in flower gardens in this
country as an ornamental plant. The leaves are used in medicine, those
from plants of the second year's growth being required for the official
drug.
Digitalis thrives in ordinary well-drained garden soils of open texture
and reasonable fertility. Sowing the seed directly in the field
occasionally gives good results, but is so often unsuccessful that it
can not be recommended. The seeds are exceedingly small and do not
germinate well except under the most favorable conditions. They should
be mixed with sand, to insure even distribution in seeding, and sown
as early as February in seed pans or flats in the greenhouses or in
well-protected frames. When danger of frost is past the plants should
be hardened off and transplanted to the field, where they may be set
about a foot apart in rows spaced conveniently for cultivation.
The plants do not flower until the second year, and it is necessary to
cultivate them frequently during the growing seasons of both the first
and second year. In localities where the cold weather is severe it may
be desirable to protect the plants during the first winter with a light
mulch of straw or coarse farmyard manure.
The plants usually flower in June of the second year, and the leaves
may then be collected. They are carefully dried in the shade and should
be stored in such a manner that they will not be exposed to light
and moisture. The results of experiments indicate that yields of 450
to 600 pounds of dry leaves per acre may be obtained under favorable
conditions. In considering digitalis culture it should be borne in
mind that the crop occupies the soil for the greater part of two
seasons and demands even closer attention than many truck or garden
crops.
In 1919 small areas of cultivated digitalis, ranging from one-half
to 1 acre in extent, were harvested in Pennsylvania, South Carolina,
Washington, California, and some other States. Several tons of
digitalis leaves were also collected from plants of wild growth in the
general region of the Coast Range of mountains on the Pacific coast.
Digitalis is of great medicinal importance, but on account of its
potency is administered in very small quantities; consequently, a few
thousand pounds is sufficient to meet the annual market requirements.
Before the war the price for digitalis leaves averaged about 15 cents a
pound; in June, 1920, it was about 35 cents a pound.