Aerial photo taken on June 27, 2018 shows farmers working in the field planted with Danshen in Chinese, or Salvia miltiorrhiza in Latin, an indigenous Chinese herb, in Tiangezhuang Village of Tangshan City, north China's Hebei Province, June 27, 2018. (Xinhua/Mu Yu)

Farmers work in the field planted with Shegan in Chinese, or Belamcanda chinensis in Latin, an indigenous Chinese herb, in Tiangezhuang Village of Tangshan City, north China's Hebei Province, June 27, 2018. (Xinhua/Mu Yu)

A farmer shows dried Danshen in Chinese, or Salvia miltiorrhiza in Latin, an indigenous Chinese herb, in Tiangezhuang Village of Tangshan City, north China's Hebei Province, June 27, 2018. (Xinhua/Mu Yu)