Gua Lou Pi
Botanical name: Trichosanthes kirilowii
Common name: Trichosanthes fruit peel, Chinese cucumber, Snakegourd
Family: Cucurbitaceae, gourd family
Part used in Chinese medicine: fruit peel
Major Chinese medicine actions:
Clears Lung heat, transforms phlegm, regulates qi of the chest,
Photo Credits: (top to bottom)
Photo 1: Trichosanthes kirilowii; 08/2002; author Michael Wolf; permission under GFDL
Trichosanthes is a perennial, twining, quick-growing vine with decorative feathery white flowers and round fruits that turn from yellowish green to yellow or orange red with maturity. Native to Japan and China, the plant is grown for its young fruits which are pickled, for its leaves and young shoots that are cooked as a vegetable, and the roots which are used fresh in cooking or dried for Chinese herb decoctions. When the root is used for food, it harvested in the fall, cleaned, cut into thick slices, and soaked for 4-5 days. The water is changed daily until the root disintegrates and can be mashed into a fine pulp. This starchy mass is used for making cakes and dumplings.
Growing and Propagation
The plant grows quickly to a height of 6 feet, or up to 20 feet in very warm climates. It is hardy only to USDA zone 8, about 20 degrees F, but the tubers can sometimes survive the winter underground, even in the snow. The plant can be grown as an annual, or the large tuber can be stored in a cool, frost-free, dry place in winter and replanted in spring of the following year. It grows best in humus rich, fertile, well-drained soil, and in full sun at a minimum of 68 degrees F. The soil should be dug deeply to a depth of 2 feet so that the tuber can grow easily, and the plant requires regular watering during the growing season
Flowers bloom from July to September, and seed ripens from September to October. The plant is dioecious, so there must be both a male and female plant in order to produce fruit. For fruit production, propagation done by seed is best, while root division is best for root production. Seed is sown in spring in a warm greenhouse, and seedlings planted outside as soon as possible after the last frost. Germination will be facilitated by soaking the seeds in warm water for 24 hours before planting.
Male plants are considered best for root division. Roots should be dug in the fall, and healed in sand over the winter. Before they begin to grow leaves in the spring, the roots are divided into 3-5 inch sections and planted about 6 inches deep.
Harvesting and Preparation
Several parts of the Tricosanthes plant are used in Chinese medicine. The root is Tian Hua Fen, the whole fruit is Gua Lou, the fruit peel is Gua Lou Pi, and seeds are Gua Lou Ren. Roots are harvested in late fall when the plant is dormant. The small rootlets are removed and the root bark shaved off. Large roots may be split, then cut into oblique slices and dried in the sun.
The fruit is harvested when very ripe, in late autumn just before winter. When the surface of the fruit starts turning yellow and begins to develop a white powdery exterior, it is completely ripe. It is harvested with the stem intact and groups of the fruits are hung together to dry in the shade for about two months. The stems are removed at that time. In rainy regions, the excessive moisture can easily cause molding and mildew, so the fruits are cut into sections and dried more quickly.