Hemp is a fast-growing, herbaceous, annual plant. It can grow in height from 1.5 to 5.0 metres, has a stem diameter of up to 4cm and has a deep tap root. Hemp is believed to have originated in the highlands of the Himalayas, and spread out from this region. China has farmed and cultivated hemp for its strong fibre since at least 8000 BC. Along with silk, hemp was a key textile in China and used by many for clothing because it was less expensive than silk.