Burdock (Arctium lappa) is a large biennial plant well known as a common and troublesome weed in the Eastern and Central States and in some western localities. The dried root from plants of the first year's growth forms the official drug, but the seeds and leaves are also used medicinally.

Burdock will grow in almost any soil, but the best root development is favored by a light well-drained soil rich in humus. The seeds germinate readily and may be sown directly in the field, either late in the fall or early in the spring. The seed may be sown in drills 18 inches or 3 feet apart, as desired, and should be sown 1 inch deep if in the fall, but less deeply if sown in the spring. When the seedlings are well up they should be thinned to stand about 6 inches apart in the row. Cultivation should continue as long as the size of the plants will permit.

The roots are harvested at the end of the first year's growth in order to secure the most acceptable drug and also to prevent the plants from bearing seed and spreading as a weed. The tops of the plants may be cut with a mower and raked off, after which the roots can usually be turned out with a deep-running plow or with a beet lifter. In a dry and very sandy soil the roots frequently extend to a depth of 2 or 3 feet, making it necessary to dig them by hand. After digging, any remaining tops are removed and the roots are washed and dried, the drying being preferably by the use of low artificial heat. The roots are usually split lengthwise into two or more pieces in order to facilitate drying, although whole roots are marketable.

Yields at the rate of 1,500 to 2,000 pounds of dry roots per acre have been obtained. The prewar prices offered by dealers ranged from 4 to 6 cents a pound. The prices for the root and seed in June, 1920, were 12 cents a pound each.