Sisal is a plant of the Agave family and consists of a rosette of sword-shaped leaves about 1.5 to 2 metres tall. The leaves contain valuable fibres, which account for only 4 % of the plant weight. After a period of eight to ten years the mature plant sends up a central flower stalk reaching about 6 metres in height. Flowers form dense clusters at the ends of branches growing from the flower stalk.