Vetiver: The Miracle Grass

1. Vetiver: The Miracle Grass Stuart Nicholson.

2. What is Vetiver? • Origins • Uses • What’s special ? • Challenges • The Future

3. What is Vetiver? • Vetiveria is a genus of stiff-leafed perennial grasses belonging to the family Graminaceae. • It grows to a height of 2m and has a strong, dense, fibrous root system which grows mainly vertically and frequently to depths of more than 3m. • It is, by nature, a tropical hydrophyte, but often thrives under xerophytic and semi-temperate conditions.

4. What is Vetiver? • There are 12 species of vetiver naturally occurring in different parts of the world, and several hundred cultivars, but almost all of the conservation work uses Vetiveria zizanioides, which originates from the Asian sub-continent. Other species with are also used to some extent are V. nigratana from Southern Africa and V. nemoralis from South East Asia. (Southern Africa Vetiver Network website, 2002)

6. Origins • The Vetiver System was first developed in the mid 1980s by the World Bank for soil and water conservation in India. (Truong, P. 2000). It is based on a two-fold approach to these issues, using Vetiver grasses planted in hedgerows. These are: • 1) To stabilise soils with the deep, dense, fibrous root networks. • 2) To slow down surface run-off with the leaf/ stem systems so that sedimentation of eroded material, and increased infiltration of water, occurs.

7. Origins • Since these early days, a worldwide network of vetiver enthusiasts has formed, who exchange ideas and technologies. As a result, many other uses for vetiver have been “discovered” and developed.

8. Uses. • Its primary use is still for soil and water conservation, but these uses have been developed and many extra uses are being promoted. • Vetiver essential oils are used in the perfume and aromatherapy industries- it is extracted from the roots by distillation, at a rate of 1% -1.5% of the dry matter weight. • The leaves are used for fodder- either fresh, ensiled (silage) or dried. • The leaves are used for traditional weaving- mats,baskets, hats, lampshades, book covers etc. • The leaves are used for thatching.

9. Photos by Criss Juliard

10. Uses. • Leaves used for paper-making, crop mulch, mud-brick reinforcing, and fuel. • Root extract used for perfume, disinfectant, antiseptic, insecticide and “water purifier” (Senegal and Mali) (Julliard,C.) • The plants are also used for Wastewater treatment (Australia), Agrochemical Pollution control (Australia, USA), Algal Bloom control (Vietnam), Landfill Leachate control (China, Thailand, Australia, USA), Mine dump stabilisation (South Africa), Water Quality improvement in Acid Sulfate soils (Australia) and Civil Engineering works stabilisation (many countries)

11. Datianshan Landfill site, Guangzhou, Quangdong Province, China Photos from TVN Acid Sulfate Soil drains in Queensland Australia. Photo by Paul Truong. Xinchang Railway Embankment Stabilization. China Photos by Liyu Xu

12. What’s special? • Vetiveria zizanioides does not spread by itself- any seeds produced are sterile, and it has no stolons and only very short rhizomes. This means that it will not “escape” from its planted area and become an invasive weed. • Vetiver has a tolerance for growing in a wide variety of climatic and environmental conditions and has a very high ability for survival of extreme events. • Vetiver grasses are essentially tropical plants, but they also survive well in many semi-temperate regions. Optimal root growth occurs at a temperature of 25oC, but plants have survived surface temperatures of as low as -22 oC for short periods in Northern China (Wang,Y.W. 2000).

13. Arsenic Chromium. pH & Manganese. Copper. Salinity.

14. What’s special? • Vetiver plants are not killed by fire, the leafed portions can be burnt away, but they will grow again from the sub-surface part of the plant. • V. zizanioides grows best in regions that have a rainfall above 700mm per year, but it will survive on as little as 300mm. Its deep roots make it very resistant to extended drought conditions. It is also very tolerant of wet conditions and survives total submergence for up to 3 months.

15. What’s special? • The roots system of Vetiver species grows vertically downwards, there is little tendency for lateral exploration, therefore it is not very competitive with crops planted alongside it. Although there are many other plants that have extremely vigorous and extensive root networks, they tend to be either highly competitive or very invasive. (Tscherning, K. et al 1995)This may not be a problem if the vegetation is simply being used to stabilise soil structures against erosive action, but if the aim of the project is also to do some form of intercropping or to limit the extent of spread of the ground-cover, then Vetiver tends to be a better option.

16. Two month old roots (72cm) from floating platform. Extensive one year old root system. Fire damage recovery- 6 months. Two year old, two metre root system. One year old, 3.3m deep roots Photos from TVN. Dense root crown

17. What’s special? • Vetiveria zizanioides has roots that grow out of the stem above the base. This means that as sediment accumulates, new roots will develop near the surface of the sediment which will bind it in situ and prevent it from being eroded again. Photos from Criss Julliard.

18. From Criss Julliard, Senegal Report.

19. Challenges to the System. • Although Vetiver usage has become a very robust system, there are a number of points that need to be followed to prevent the system failing. • The slips need to be kept moist before planting out and need to be watered in to establish themselves. Moist soil conditions are necessary for the first couple of months, so irrigation may be needed. • Plant spacing is extremely important for effective erosion control. The slip material should be spaced about 15cm apart for it to form a thick hedge quickly.

20. Challenges to the System. • Not having viable seed means that root material from nurseries and actual planting out of slips must be done by hand. This process is very labour intensive and takes a lot of time, so large areas cannot be done very quickly. • For erosion control to be effective, the plant rows must be spaced within certain horizontal and vertical distance criteria- this requires a certain amount of technically informed knowledge on the part of the planners. This is not always available where it is needed. • Vetiver species are not tolerant of shade. They will not survive conditions of more than 50% shading over a long period of time.

21. Close planting spacing ensures a good, dense hedgerow. Labour intensive transplanting. Dense hedgerows. Close planting ensures sediment entrapment. Photos from TVN.

22. The Future? • There is likely to be a continued expansion in the use of Vetiver grasses for conservation exercises, with little modification to the genetic material required to make it almost universally acceptable. It would benefit from better acclimatization to temperate regions and, in some instances, to increased shade tolerance. Higher nutritional content would also obviously be an advantage in some circumstances. • The greatest increase in its usage will come from improved dissemination of information for correct systems application. This will occur through extension service networks.