Salix babylonica (Babylon Willow or Weeping Willow; Chinese: 垂柳; pinyin: chuí liǔ) is a species of willow native to dry areas of northern China, but cultivated for millennia elsewhere in Asia, being traded along the Silk Road to southwest Asia and Europe.
The cultivar 'Tortuosa' was introduced into North America in 1923 when Arnold Arboretum received a cutting from China, it was named the next year and entered commerce during the 1930s. 'Tortuosa' in Latin means 'full of crooks or turns'.
'Tortuosa' is a variety grown for its interesting stems and foliage. It is often referred to as the 'Corkscrew Willow', due to the contorted nature of the stems. The fine and lush foliage emerges in mid spring, ages to a darker green, then develops yellow tones in autumn before falling. The foliage is held on pendulums stems, as the tree matures to 15m tall and around 8m wide. It can be kept smaller than this with regular pruning. It can be grown in sun or shade, but needs soils which are nearly always moist.