Comfrey is native to Europe and the temperate regions of Asia. It also grows in Australia. It is a hearty perennial herb that was introduced and naturalized in the United States. It can be found in rich, wet soils along streams and river banks, in ditches and damp meadowlands. Comfrey grows best in moist soil and in sunny areas, but needs shade in the hottest climates. It will keep its leaves throughout the winter in virtually frost free climates; otherwise it will die to the ground in fall. Comfrey can be grown by seed, but grows best from cuttings. It spreads easily from its roots and therefore is difficult to eradicate. One should think carefully about where to place comfrey in the garden.
Some identifying characteristics of comfrey are its hairy stem and leaves. It stands 2-3 feet high, freely branched at the joints, rough, angular, and hollowed. Its leaves are ovate to lanceolate, and the upper leaves are smaller, fewer and hug the stem. The lower leaves are very large, and many are on long green petioles, with wavy margins. The flowers are pale whitish or pale purple, terminal to the many branches, somewhat long and hollow resembling an elongated bell. The seeds are small and black. The root is spindle-shaped, thick with a brownish-black bark, or gray and horny wood. The roots are branched and penetrate deeply into the earth. They are deeply wrinkled, have short fractures with short wood bundles and broad medullary rays.