What is the correct method for harvesting Chinese medicinal herbs
The rational harvesting of Chinese medicinal herbs (season, time, method) is not only important for ensuring the quality and efficacy of the medicinal materials, but also significant for protecting and expanding medicinal resources. When harvested at the right time and in the right way, the medicinal properties are strong and the therapeutic effect is high; otherwise, the medicinal properties are weak and the therapeutic effect is poor. For example, the alkaloid content of Ephedra (mahuang) is highest in August-September, so it should be collected in August-September; senna leaf (fanxieye) grown for about 90 days contains the highest level of anthraquinone active ingredients, so it should be collected at that time; Gastrodia elata (tianma) collected in winter when the stem and flower have not yet emerged, known as winter tianma, is heavy and of good quality, while spring tianma collected after the flower stem has emerged is inferior. Chinese medicinal herbs should be collected when the active ingredient content is highest, but the patterns of increase and decrease of active ingredients in Chinese medicinal herbs are not yet clearly understood, so traditional experience can be followed, mainly guiding the harvest of various types of medicinal materials based on factors affecting the traits and quality of the medicinal materials, the difficulty of harvesting, and the general patterns of nutrient fluctuation during the growth and development of animals and plants.
The harvesting of medicinal materials must be carried out at the time when the different medicinal parts and active ingredient content are at their highest, in order to obtain high yield and high quality. These are described separately below:
I. Roots and rhizomesRoots and rhizomes are the storage organs of plants. When the above-ground parts begin to grow, they often consume the nutrients stored in the roots, so they should be harvested during the dormant period when plant growth has stopped and flowers and leaves have withered, or before germination in spring. For example, kudzu root (gegen) harvested in late autumn and winter is solid and full of starch, but if harvested in spring after the above-ground parts have grown, it has no starch at all and becomes woody, and cannot be used as medicine. For wild medicinal plants, after the above-ground parts wither in winter, they are difficult to find, so late autumn, before the seedlings wither, is preferable. But there are exceptions, such as bupleurum (chaihu), saposhnikovia (fangfeng), and changium (mingdangshen), which are better collected in spring; pseudostellaria (hai'ershen) is collected in summer; corydalis (yanhusuo), pinellia (banxia), and Stephania (xiatianwu) should be dug between Grain Rain and the Beginning of Summer. The general digging method is to use special tools to dig when the soil is moist after rain; for ginseng, the fibrous roots must be protected. Root and rhizome medicinal materials often need to grow for more than one year before they can be used as medicine, generally 2-5 years; among cultivated medicinal materials, white peony (baishao) needs 3-4 years of growth, and ginseng needs more than 5 years; wild ones grow even longer, for example, wild astragalus (huangqi) needs 2-3 years before being dug.
2. Root bark and tree barkRelatively speaking, bark is mostly collected from Qingming to the Summer Solstice, when there is more sap in the plant body, cambium cells divide rapidly, the bark is easy to peel off, and the active ingredient content is high, such as Eucommia (duzhong) and magnolia bark (houpo). Root bark is collected in winter, such as moutan bark (mudanpi) and lycium root bark (digupi). For some medicinal materials from which bark is taken, it can be collected when timber is being harvested. The harvesting of root bark and tree bark easily damages plant growth, so attention should be paid to the harvesting method. Tree bark must not be peeled in a complete ring, otherwise the conducting system is destroyed and the tree dies; root bark is peeled after the roots are dug up.
3. Leaves and whole plants. These should be harvested when the plant is growing most vigorously, or when the flower buds are about to open, or when the flowers are in full bloom but the fruits and seeds are not yet ripe, because at this time the plant has fully grown and its vitality is at its strongest. For example, ginseng leaves are collected in summer, when the leaves are dark green and luxuriant. But mulberry leaves need to be collected after frost, and loquat leaves and ginkgo leaves need to be collected after they have fallen to the ground. Whole plants are mostly harvested at the flowering stage, cutting the plant stems from the upper part of the root, or pulling up the entire plant; some only collect the flowering branch tips, but some collect young seedlings, such as Artemisia capillaris (yinchenhao), which should be collected in early spring when it is a seedling.
4. FlowersSpecial attention must be paid to the collection time of flower medicinal materials, because the flowering period is generally short, and if the collection time is improper, it greatly affects the quality of the medicinal materials. Usually they are collected when the flowers are open or about to bloom, such as Inula (xuanfuhua) and chrysanthemum (juhua), which are collected when they first open; honeysuckle (yinhua) and biond magnolia flower (xinyihua) are collected when about to bloom; sophora flower (huaihua) and clove (gongdingxiang) are collected at the bud stage. Generally, they should not be collected after the flowers are in full bloom, because at that time the active ingredient content decreases, affecting efficacy, and the petals easily fall off, worsening quality. For example, safflower (honghua) is yellow when it first opens, then turns orange-red, and finally turns dark red; collection when orange-red is best. Flowers should be collected on a clear morning when the dew has just dried, to facilitate rapid drying. For prickly plants such as safflower, they should be collected when the dew has not yet dried; after it dries, the thorns on the plant stems and bracts can prick the fingers of the collectors.
5. Fruits and seedsExcept for a few medicinal materials such as green tangerine peel (qingpi), green plum (qingmei), and bitter orange (zhishi), which must be collected when immature, fruits should generally be collected when they have fully grown or are nearly ripe; juicy berries spoil easily and must be collected and processed promptly; dry fruits and capsules must be collected at the right time before maturity, otherwise they will split open and scatter after ripening. Seed medicinal materials must be collected only after they are fully ripe; when collecting, pick them by hand or cut them off with branches, dry them in the sun, and then gather them.
6. Fungi, algae, and sporesSclerotia, algae, and spore medicinal materials are collected according to their respective characteristics. For example, Poria (fuling) collected after the Beginning of Autumn is of better quality, and puffball (mabo) is collected when the fruiting body has just matured; if too late, the spores scatter.
7. Animal-derivedThe collection of animal-derived medicinal materials varies with the type of medicinal material. For example, for insect-derived medicinal materials, one must grasp their hatching, development, and activity seasons. For example, cicada slough (chanyi) is collected in summer and autumn when the black cicada molts; mantis egg case (sangpiaoxiao) must be collected before March, otherwise the eggs hatch into adults; earthworms are caught in June-August when they first begin to be active; centipedes are better caught around Qingming; generally, winged insects mostly rest on plants in the early morning when the dew has not yet dried and are not easy to fly away, making them easy to catch, such as blister beetles (banmao) and gadflies (mengchong). For the animal medicine forest frog (hashima), it enters hibernation in late autumn, making it easy to catch, and there is more oviduct fat in its body; deer antler velvet is cut 40—60 days after Qingming (May-July); if too late, it becomes keratinized and is no longer velvet. For animal medicines such as bear bile, cow bezoar, musk, horse bezoar, and toad venom, these are collected after capture or at slaughterhouses. In recent years, there have also been new collection methods such as artificially cultivating cow bezoar, extracting musk from live musk deer, and extracting bile from live bears.
8. Mineral-derivedMineral medicinal materials can be collected at any time, and can also be collected in conjunction with mining. In the collection of medicinal materials, attention should be paid to protecting medicinal resources. Planting should be planned and collection should be planned; collect only as much as is used, and do not store too much, causing oversupply and leading to deterioration and waste. Collection should also be rational, such as collecting the large and leaving the small, preserving the rare and collecting the dense, rational rotational harvesting, closing the mountains to cultivate medicinal resources, and introducing and propagating species, so that medicinal resources are inexhaustible.