Cultivating Forsythia viridissima: Tips and Techniques

Forsythia viridissima: Medicinal source: The fruit husk, root, or leaves of the Forsythia viridissima, a plant in the Oleaceae family.

Harvesting and storage: The fruit is harvested in summer and autumn, dried; the root can be dug up all year round, cleaned, cut into sections, used fresh or dried; the leaves can be collected in spring, summer, and autumn, used fresh or dried.

Ecological environment: It grows in slopes, riversides, and forest edges. Functions: Clears heat, detoxifies, and disperses stagnation. Used for treating common cold with fever, and red and swollen eyes.

I. Plant morphology

Forsythia viridissima is a deciduous shrub that can grow up to 3 meters tall. Except for the ciliate margins of the sepals, the entire plant is hairless.

The branches are brown or reddish-brown, upright, with small branches that are green or yellow-green, four-sided, with visible lenticels and pith. The leaf blades are oblong to lanceolate, or inverted ovate-oblong, measuring 3.5-15 cm in length and 1-4 cm in width.

The apex is sharply pointed, the base is wedge-shaped, usually with irregular sharp serrations or coarse serrations on the upper half, rarely nearly entire, dark green on the upper surface, light green on the lower surface, both surfaces hairless, with the midrib and lateral veins slightly concave on the upper surface and convex on the lower surface; petioles are 6-12 mm long.

The flowers are axillary, blooming before the leaves; flower stalks are 3-7 mm long; sepals are 3.5-5 mm long, green, ovate, wide-ovate, or wide-elliptic, 2-4 mm long, with ciliate margins; corolla is deep yellow, 1.1-2.5 cm long, corolla tube is 5-6 mm long, lobes are narrow-oblong to oblong, 0.6-1.8 cm long, 3-8 mm wide, with orange stripes at the base on the inner surface, and recurved; in flowers with stamens measuring 3.5-5 mm long, pistils are 5.5-7 mm long, while in flowers with stamens measuring 6-7 mm long, pistils are about 3 mm long.

The fruit is ovate or wide-ovate, 1-1.5 cm long, 0.6-1 cm wide, slightly rounded at the base, gradually pointed at the tip, with lenticels; fruit stalks are 3-7 mm long. Flowering period is from March to April, fruiting period is from August to November.

II. Ecological environment

It grows in slopes, riversides, and forest edges. It is a temperate and subtropical tree species that prefers partial shade, is drought-tolerant, cold-tolerant, but intolerant of waterlogging. It grows on gently sloping semi-shady slopes at altitudes of 400-1200m.

III. Cultivation techniques

Forsythia viridissima can be propagated by seeds, cuttings, layering, and division, but propagation by cuttings is the most convenient. Hardwood cuttings can be used in spring, and softwood cuttings can also be used in summer.

Field management: During transplantation, strong pruning should be done to reduce water and nutrient consumption, promote survival, and water should be appropriately irrigated during drought. Fertilizers can be applied in moderation during summer.

Harvesting and storage: The fruit is harvested in summer and autumn, dried; the root can be dug up all year round, cleaned, cut into sections, used fresh or dried; the leaves can be collected in spring, summer, and autumn, used fresh or dried.

IV. Medicinal parts

Macroscopic identification: The leaf blades are wrinkled, curled, and become elliptical or lanceolate after being flattened. They are 5-14 cm long and 1.5-4 cm wide, with a sharp apex and a wedge-shaped base.

The edges have serrations, the upper surface is dark green, and the lower surface is light green. The leaf stalks are 0.5-1 cm long. The odor is slight, and the taste is bitter. The fruit is ovoid, 1-1.5 cm long, with a diameter of about 1 cm.

It often splits into two separate fruit lobes, with residual membranous septa in the middle of each lobe, which are curled outward at the apex and bluntly rounded at the base.

The surface is yellow-brown to yellowish-brown, with irregular longitudinal and transverse veins, and numerous small tubercles are distributed on both sides of the longitudinal groove from the middle to the top.

The base has a fruit stalk or fruit stalk scar. It is hard and brittle. The odor is slight, and the taste is bitter.

V. Microscopic identification

Transverse section of the fruit peel: The outer fruit peel consists of a single layer of cells, elongated in the longitudinal direction, and covered with a horny layer.

At the tubercle, there is a raised thin tissue, and the outer fruit peel breaks and disappears at this point. The middle fruit peel consists of multiple rows of thin-walled cells, which are oval or elongated and arranged irregularly; there are scattered collateral vascular bundles.

The inner fruit peel consists of multiple rows of thick-walled cells, accounting for about half of the thickness of the fruit peel.

The cells are square or elongated, embedded and arranged in the transverse direction, with obvious pore canals. The inner epidermis consists of a single row of cells, elongated in the longitudinal direction.

VI. Physicochemical identification

Thin-layer chromatography: Take 0.5 g of the coarse powder of the herb, add 5 ml of 95% ethanol, cold soak for several hours, concentrate the filtrate to 0.5 ml as the test solution; use oleanolic acid ethyl acetate solution as the control.

Spot the samples on the same silica gel G-plate, develop with petroleum ether-benzene-ethyl acetate-acetic acid (10:20:6:0.5) for 13 cm, remove and air dry, and fumigate in iodine vapor.

The chromatogram of the test sample should show spots of the same color as the chromatogram of the control at the corresponding positions.

VII. Additional information

Source: The roots, leaves, and fruit husks of the Forsythia plant in the Oleaceae family.

Functions: Clears heat, detoxifies, and dispels dampness.

Main Uses: Used for treating influenza, red and swollen eyes, scabies, joint and bone pain, and cervical lymphadenitis.

Nature and Taste: Bitter, warm. Enters the lung and liver meridians.

Dosage: Internal use: Decoction, 9-15 grams. External use: Apply an appropriate amount to the affected area.

Latin Name: Forsythia viridissima Lindl

Pharmacological Characteristics: Bitter in taste; cold in nature.

Effects: Clears heat, detoxifies, and disperses stagnation.

Main Uses: Used for treating fever caused by common cold, and red and swollen eyes.

Dosage: Internal use: Decoction, 10-15 grams; double the dosage for fresh materials. External use: Use an appropriate amount, decoct and wash.