Oolong tea is called Blue(green) tea.
Oolong tea is a Semi-oxidised tea. It has the most complex making process from the 6 basic types of Chinese Tea.
It grows in 4 main areas of China：
1) Northern Fujian(Wuyi Mt.): It is also known as Rock Tea or Wuyi Rock Tea
2) Southern Fujian(Quanzhou): It is well known for Iron Goddess etc.
3) GuangDong(Chaozhou): It is also known as DanCong from Phoenix Mt.
4) Taiwan(Whole island): It is well known for its high mountain tea
Tea trees have been successfully planted in Tai Wan from the Qing Dynasty in 1810. Since then the tea industry has become one of the main industries in Taiwan. Oolong tea from Taiwan is more famous than its red tea.
Dong Ding Oolong, is one of the famour oolong tea from JiaYi Xian in Taiwan. Higher fragrant and longer after taste may from higher altitude where the tea trees growing.