The medicinal value of plants used in Chinese herbology depends on the season and the period of growth that the plant is collected in. This has a direct influence on the quality and efficacy of the herb. Therefore, it is extremely important that the plants are picked at a time when their potency is at its peak level. Different plants and different parts of the plants have different times that are ripe for picking.
Whole plants, stems and leaves are mostly collected when they are in full bloom or in early blossom. This is done by either cutting off parts above the ground or by pulling up the plant from its roots.
Flowers are generally collected as buds or in early blossom in order to avoid the loss of fragrance and petals. Pollen is collected in full bloom.
Fruits and seeds are generally collected when ripe. Some fruits are collected unripe, such as black plums, tangerines and bitter oranges.
Roots and rhizomes are generally collected in early spring before they sprout or in late autumn when the stems and leaves begin to wither.
Bark is generally collected in spring and summer when it is abundant in fluid and nutrients, and can be easily stripped off. Root bark, such as mountain and wolfberry root bark, should be collected in autumn.
Seedlings or withered leaves are also used in Chinese herbal remedies, such as oriental wormwood and mulberry leaf. A small number of herbs can be collected in summer, such as pinellia tuber and corydalis tuber.