Chinese Foxglove

A genus of eight or nine species of perennials that occur in E Asia. A few species are cultivated for their large, foxglove-like flowers; they tend to deteriorate after the first year and are therefore often grown as biennials. Rehmannia glutinosa was the first species of the genus to be cultivated in the West. It has been superseded by R. elata as an ornamental. However, due to its long cultivation for medicinal purposes, many variants of R. glutinosa are available in China, differing in size, habit, and root flavor. Rehmannia glutinosa is one of the most popular tonic herbs in Chinese medicine and among the 50 most important Chinese herbs. The fresh or dried roots (sheng di huang) were first mentioned in Chinese medical literature during the Han dynasty (206BCE-CE23). Roots steamed in rice wine, known as shu di huang, were described in the Illustrated Classic of the Materia Medica by Su Song (CE1061). Rehmannia was named after Joseph Rehmann (1799-1831), a German physician.

Purple-hairy, sticky perennial with slender, tuberous, orange roots and a basal rosette of ovate, scalloped leaves, to 10cm (4in) long, which often have reddish undersides. Red-brown to dull yellow, purple-streaked, pendend, tubular flowers, to 5cm (2in) long, with flared, lobed mouths, appear from spring to summer, followed by ovoild seed capsules.


Common Name:
Chinese Foxglove
Botanical Name:
Rehmannia glutinosa
Genus:
Rehmannia
Family Name:
Scrophularaceae
Native Location:
N China
Cultivation:
Light, moist, well-drained, rich, neutral to acid, sandy soil in sun. Plants are prone to fungal infections, especially in damp conditions.
Propagation:
By seed sown in late winter at 13-16°C (55-61°F); by root cuttings in late autumn; by softwood cuttings of basal shoots in spring.
Harvest:
Roots are lifted in autumn and eraly winter (cultivated crop), or early spring (wild plants), and used fresh or dried (sheng di huang), for use in decoctions, extracts, pills, powders, and tinctures, or steamed in rice wine (shu hi huang).
Height:
15-30cm (6-12in)
Width:
30cm (12in)
Hardiness:
Z8-10
Properties:
A sweet, cooling (sheng di huang) to slightly warming (shu di huang) herb that controls bleeding, lowers fever, reduces blood sugar, and has diuretic and anti-bacterial effects (sheng di huang). It acts as a tonic for the heart, blood, and kidney energy, regulates menstruation, and strengthens women after childbirth (shu di huang).
Medicinal Uses:
Internally for thirst associated with feverish illnesses, heat rash, hemorrhage of all kinds, excessive menstruation, and diabetes (sheng di huang); anemia, night sweats, menopausal problems, weakness following childbirth, and involuntary ejaculation (shu di huang). Often combined with Angelica polymorpha var. sinesis (See, Chinese Angelica), the peel of Citrus reticulata (See, Mandarin Orange), and Ziziphus jujuba (See, Chinese Date).
Warning:
Not given to patients with digestive problems.
Parts Used:
Roots (di huang)
Bibliography:
Encyclopedia of Herbs ~ Deni Bown ~ Copyright © 1995, 2001, Doring Kindersley Limited ~ pp. 341-342