Vetiver

Description

Chrysopogon zizanioides, commonly known as vetiver and khus, is a perennial bunchgrass of the family Poaceae. Vetiver is most closely related to Sorghum but shares many morphological characteristics with other fragrant grasses, such as lemongrass (Cymbopogon citratus), citronella (Cymbopogon nardus, C. winterianus), and palmarosa (Cymbopogon martinii). Vetiver grows to 150 centimetres (5 ft) high and forms clumps as wide. Under favorable conditions, the erect culms can reach 3m in height.The stems are tall and the leaves are long, thin, and rather rigid. The flowers are brownish-purple. Unlike most grasses, which form horizontally spreading, mat-like root systems, vetiver's roots grow downward, 2 metres (7 ft) to 4 metres (13 ft) in depth. The vetiver bunch grass has a gregarious habit and grows in tufts. Shoots growing from the underground crown make the plant frost and wildfire resistant, and allow it to survive heavy grazing pressure. The leaves can become up to 300 centimetres (10 ft) long and 8 millimetres (0.3 in) wide. The panicles are 15 centimetres (6 in) to 30 centimetres (12 in) long and have whorled, 25 millimetres (1 in) to 50 millimetres (2 in) long branches. The spikelets are in pairs, and there are three stamens. The plant stems are erect and stiff. They can survive deep water flow. Under clear water, the plant can survive up to two months. The root system of vetiver is finely structured and very strong. It can grow 3 metres (10 ft) to 4 metres (13 ft) deep within the first year. Vetiver has neither stolons nor rhizomes. Because of all these characteristics, the vetiver plant is highly drought-tolerant and can help to protect soil against sheet erosion. In case of sediment deposition, new roots can grow out of buried nodes. Though it originates in India, C. zizanioides is widely cultivated in tropical regions. The major vetiver producers include Haiti, India, Indonesia, and Réunion. The most commonly used commercial genotypes of vetiver are sterile (do not produce fertile seeds), and because vetiver propagates itself by small offsets instead of underground stolons, these genotypes are noninvasive and can easily be controlled by cultivation of the soil at the boundary of the hedge. However, care must be taken, because fertile genotypes of vetiver have become invasive.