The experiences described in the previous chapter seem to promise a new and perhaps invaluable technique for controlling erosion in the tropics. However, it should not be thought that John Greenfield and Richard Grimshaw were the first to promote vetiver. On the contrary, this plant is one of the better known crops of the tropics. It is only for erosion control that their efforts stand out.
For several centuries vetiver has been commercially cultivated for the scented oil that can be distilled from its roots. This is a treasured ingredient in some of the world's best-known perfumes and soaps and, largely because of its potential as an export commodity, vetiver can be found in at least 70 nations (see table next page). Indeed, during the last century, wherever British, French, and other colonial administrators were assigned, they typically established test plots of essential oil crops—vetiver, citronella, and lemongrass, for instance. In most cases, vetiver still remains in those plots, but only a handful of countries produce the oil commercially (see sidebar, page 78).
Despite this, however, in most places use of the grass to halt soil loss is virtually unknown. Nonetheless, the plant's ability to control erosion is not new. Before World War II, some tropical countries deliberately planted vetiver hedges as contour barriers. This was particularly true in the sugarcane fields of the British Caribbean. However, this technique was essentially forgotten during the disruptions of the war and of the independence that soon followed in many nations. With both the war and the collapse of colonialism, many agricultural advisors left the tropics, taking the knowledge of this technique with them. By the 1960s, only a few people in the former colonies remembered that vetiver could stop erosion.
But vetiver is so persistent that even where it has been abandoned, it has continued to survive for decades or even centuries. For this reason, therefore, the plant can be found throughout the tropics as well as in a few other (sometimes completely unexpected) areas.
Below, we highlight the findings from a correspondence campaign
TABLE 1 Countries Where Vetiver is Currently Known To Exist
Central African Republic
aimed both at locating the grass and at roughly assessing the worldwide experiences with it.1
Vetiver is an Asian plant, probably native to a lowland, swampy area north of New Delhi in India. It has therefore been known to Asians longer than to anyone else.
In India, vetiver, or khus as it is more commonly known, has been used since ancient times and is recorded as a medicinal plant in the Ayurvedic era. However, it has been appreciated mainly for its
fragrant roots. People weave these roots into mats, baskets, fans, sachets, and ornaments. They also weave them into window coverings that freshen the air of thousands of village homes with a sweet and penetrating scent.2 Oil from the roots is also used in perfumes. Not only is it pleasantly fragrant, it takes so long to evaporate from the skin that perfumers include it in their soaps and scents to give them "persistence."
The living grass has also long been known as a useful soil binder. However, it was mostly planted around rice paddies, along rivers, and beside canals and ponds to strengthen the banks and keep the land from collapsing into the water.
To line it out across the hill slopes is, for most places, a new and innovative concept. However, since 1987 a number of trials in research stations and farmers' fields have been carried out under the aegis of several of India's state governments, largely with funding from the World Bank. The data is preliminary and is usually not statistically significant, but it is instructive nonetheless.
Some examples follow.3
Karnataka The state of Karnataka has taken up vetiver for watershed conservation with considerable enthusiasm. Traditionally, the state's farmers have used the grass as boundary plantings, and, although some have placed hedges across the middle of their land—an indication that they understand its value for erosion control—its use to conserve soil and moisture is essentially new.
Among the results of this exploratory research are some from Kabbanala. 4 Even in their first year, the partially formed hedges held back 30 percent more rainfall runoff than graded banks, 47 percent more than conventional contour cultivation, and 24 percent more than hedgerows of leucaena.5 In addition, they held back 43 percent more soil than graded banks, 74 percent more than contour cultivation, and 54 percent more than leucaena hedges. Moreover, apparently because of the improved soil-moisture levels, the vetiver hedgerows boosted crop yields 6 percent more than those on graded banks, 26 percent more than those on contour cultivation, and 10 percent more than those behind leucaena hedgerows.
Maharashtra and Madhya Pradesh On the black cotton soils in these two states, vetiver has also grown well. It holds back soil and some moisture but (unlike bunds) does not create pools of standing water on these heavy, ill-draining clays. This is important because these soils are so difficult to work with that at present they are only partially used: in the wet season they get too waterlogged; in the dry season they crack open. Bringing the black cotton soils into fuller use could boost India's food production because there are millions of hectares of them.
Tamil Nadu In Tamil Nadu there has been no formal governmental support thus far, but the Regional Research Station at Aruppukkotai6 began testing vetiver in 1987. Another grass and two shrubs were later added to the trial.7 Both grasses grew into hedges far more quickly than the shrubs, and both also proved better at trapping moisture. Vetiver was the best of all. It retained between 3 and 9 percent more moisture than the other plants. Soil behind it contained 26 percent more moisture than that on the control slope, which lacked protective hedges.
All in all, vetiver is starting to be accepted for erosion control. The state's department of agriculture has taken up large-scale multiplication of vetiver. Extension agents are being trained. And contour hedges are being established in selected watersheds. Ultimately, the state plans to protect much of its dryland areas with vetiver.
Andhra Pradesh The government of Andhra Pradesh has planted vetiver in several watershed-management projects. The results, however, are not completely satisfactory. Because of the state's semiarid climate, the plants take at least three years to grow together into fully functional hedges. Farmers, therefore, are as yet unconvinced of vetiver's value. Indeed, some, concluding that the plant will never do them any good, have plowed it up. Nonetheless, more than three out of four are waiting to see.
With its steep slopes and rushing rivers, Nepal is one of the most erosion-prone nations. Vetiver has traditionally been used in the lowland area known as the Terai, but only to stabilize the banks of waterways. Today, it can be found verging many irrigation canals, especially in locations where people tend to walk. The roots are commonly harvested and made into hairbrushes, among other things.
Also, basket weavers prefer vetiver stem; they say it holds paint and keeps its color better.
Given the results in neighboring India, much interest in vetiver has recently surfaced in Nepal. Both private organizations and government agencies have established nurseries and are growing the grass. They hope, primarily, to use it to protect the front lip of terraces (of which there are vast numbers), but they see it also as a possible way to stabilize roadsides and to protect (even "renovate") landslide areas. One group is trying to save a small dirt airfield by planting vetiver along the banks of a hungry river that is slowly eating it away.
All efforts so far have been in the Terai and nearby areas. Although it occurs commonly in the vale of Kathmandu, vetiver probably cannot
withstand the frigid winters of the uplands, where perhaps the most devastating erosion is occurring.
Vetiver traditionally has been used to stabilize some slopes and terraces in tea plantations around Kandy. However, its true potential for Sri Lanka Lay unappreciated until 1989 when Keerthi Rajapakse, a retired Assistant Conservator of Forests, helped establish nurseries to supply vetiver planting material to farmers. Rajapakse was elated to find that tobacco cultivators accepted this vegetative contour method with alacrity: soil washing out of hillside tobacco fields is considered to be one of Sri Lanka's major environmental problems.
The plant's ruggedness is almost legendary in Sri Lanka. It is here that people have used crowbars to plant it into bauxite soils. Also, farmers say that couch grass (a creeping weed almost impossible to keep out of crops) cannot penetrate a vetiver hedge.
Although Java is the leading producer of vetiver oil, almost nowhere in Indonesia has the grass been used in erosion control. Ironically, in some places people are convinced that it actually causes erosion. This is because harvesters often rip out the roots (for the oil they contain), leaving behind trenches that foster the severest of soil losses. This has been such a problem that vetiver cultivation has been prohibited in parts of Java. It is, however, a problem of irresponsible harvesting, and is irrelevant to hedges left in place as erosion barriers.
Vetiver is now being established in some of the other islands (in Kalimantan, for example) with some success.
Vetiver can be seen throughout the Philippines. It is reported that a few areas have traditionally cultivated it to control erosion—especially around ponds to keep silt from washing in. Nevertheless, the plant is hardly known to Filipinos at large.
Today, however, that is changing. A major project to restabilize the roads destroyed by the 1990 earthquake in Northern Luzon is relying on vetiver. A number of farmers in both Northern Luzon and Central and Eastern Visayas have put in contour vetiver hedges to stop soil losses. The International Rice Research Institute (IRRI) at Los Baños is studying the grass as a way to reduce erosion in upland rice fields and to reinforce the bunds around the paddies in the lowlands. Visayas
State College of Agriculture has found that vetiver grows well even on poor and very acid upland soils where little else can survive. 8
Although its efforts are just beginning, China is among the nations most active in studying vetiver. Massive projects have been started in a dozen soil-conservation areas. In part this is because of the promise of the early results, but it is also because soil and moisture conservation are among China's national priorities. The country annually loses as much as 400 tons of soil per hectare in certain areas. As a result, the Yellow River is supposedly the most silt laden in the world, and the dry-season levels in the Yangtze are dropping year by year as the ever thinner layer of soil on the hills absorbs less and less moisture. Thus, it is little wonder that there is an almost desperate grasping at what might possibly be a low-cost solution that can be installed on a large scale with local labor and resources.
Vetiver was introduced to China in the 1950s as a source of aromatic oil; when the oil prices dropped, the plant was abandoned. The impetus to test it for erosion control began only in 1988, when it was planted for stabilizing terraces of citrus and tea in Fujian and Jiangxi provinces. Farmers noted that the young citrus and tea plants seemed to grow better (perhaps because of wind protection or increased moisture) and the terraces no longer washed out.
In some areas, vetiver products are already widely popular. In at least one location, prunings from the contour hedges are sold to dairy farmers as a feedstuff and are replacing rice straw as bedding for animals. (The farmers like vetiver straw for bedding not only because it is cheap and rot-resistant, but because it frees up valuable rice straw for sale or for plowing back into the paddy.) Elsewhere, the leaves are employed for mulch.
Although China's Ministry of Water Resources has set up vetiver trials and demonstrations on some severely gullied lands, it is currently more interested in protecting terraces. Nowhere is this interest stronger than in the red-soils area, where engineered terraces have a long record of failing during the intense downpours that occur every few years.
Overall, the results in China have been so promising that during the next few years vetiver will be planted extensively in five provinces. Moreover, Chinese researchers have started their own vetiver information network, and the government has sponsored a number of vetiver conferences to speed up the exchange of information and results.
Already it has been learned that vetiver can be used south of the
Yangtze. However, stands have been established as far north as 36°N in Shangdong Province, where winter temperatures drop to -8°C.9 So far, there have been few "scientific" trials, but in one carefully documented case vetiver hedges decreased the amount of water running off the slopes by half.
Although the plant is not well known in Africa, it actually can be found growing in scattered locations from Cairo to Cape Town. Also, there is at least one native species that is an African counterpart to this Asian plant. A few African countries have already embarked on exploratory trials with one or both of these species.
Several examples follow.
Erosion has long been serious in Kenya, especially in the highlands where the rainfall is heavy and the soils erodible. Vetiver occurs in several locations there, although it is mostly used as an ornamental. It was probably introduced to produce vetiver oil, but it is thought that some was also brought in by a German coffee grower seeking to protect his eroding land. Recently, a government soil specialist10 found vetiver established on terraces in coffee country in the Machakos District as well as on a dam wall on a farm near Thika. He reports that the plants "are still effectively protecting the soil after at least a decade of neglect."
Vetiver, in principle, could be extremely valuable in the highlands—in plantations of tea, coffee, and pyrethrum, as well as in family gardens and along the sides of roads and tracks. Trials began in 1990 and, despite the short time, the grass is already showing promise.11
Although now all but unknown in Tanzania, tea planters used vetiver as an erosion-control barrier before World War II. Indeed, an old monograph on tea-growing there makes the following comment: "Grasses are usually detrimental in a high degree to the growth of tea, with apparently one exception, as far as trials and experience goes.
This exception is khus-khus grass [vetiver]. With its close stiff blades it is successfully used . . . in contour hedges. Its tussock habit favors its usefulness as its root system appears to be reasonably restricted in range. It needs to be kept under control by cutting."
Vetiver established on Mount Kilimanjaro, near Arusha, in the final decade of the last century still remains.
The vetiver highlighted in this report (Vetiveria zizanioides) is probably found throughout West Africa, but far more common at present is an African counterpart, V. nigritana. Whether it, too, will prove useful in erosion control is uncertain, but it has many interesting qualities nonetheless.
For example, V. nigritana occurs across the floodplains of the internal Niger Delta, a vast region (about 20,000 km2) that is inundated for half the year. Here, it occurs mainly on higher ground, and after the flood retreats it becomes lush and green and the herds are then given access to it according to traditional grazing rights. Vetiver (and a mixture of other species) thus provides crucial grazing to the people of the area. Animals take only the young sprouts, but after these are gone, the farmers burn the area to induce a flush of new growth.
For all its importance here, vetiver is not a fine feedstuff. Annual yields vary from 2 to 10 tons of dry matter, depending on the previous flood levels. The International Livestock Centre for Africa (ILCA) found that the whole plant had a digestibility coefficient of 35–40 percent when cut about 2 months after the flood retreated or after being burned—considerably less than the 60-percent level for the other native grass species in the area.
Despite these indifferent figures, however, this African vetiver occurs extensively, and it resists the harsh cycle of floods and fires better than almost any other species there.
In neighboring Burkina Faso, Vetiveria nigritana is also important. Indeed, certain tribes rely on the plant throughout their lives. For example, the Bozo (who dwell along the vetiver-covered shores of lakes as well as the Niger River) weave their huts out of vetiver grass or palm fronds.
Vetiver is commonly seen growing wild in Nigeria and probably this is mostly the African species, Vetiveria nigritana. Until recently, it
was not used for erosion control but now that is changing. Scientists in Anambra are taking the lead.
A state in the southeast, Anambra is probably the area hardest hit by erosion. It has extensive "badlands," so-called because of steep slopes and gullies that engulf the land and everything on it. Erosion is so severe that in just the last 10 years some 220 towns have lost property worth nearly 6 billion naira ($755 million) to 530 greedy gullies. More than 150 people have died from the resulting floods, slips, and cave-ins.
Alarmed, the state government in the early 1980s assembled a team of soil scientists and engineers from its ministries and universities and told them to find out how to halt the further spread of this menace. Initially, many concrete embankments were built, but to little avail. Then some of the scientists came up with the idea of planting strips of grass. Twenty-seven different species were tested; vetiver proved the fastest growing and the most effective. (Initially, V. nigritana was used, although V. zizanioides is now used as well.)
The researchers were excited by these results; however, the local people—even those most afflicted by erosion—remained unconvinced. The plants looked too weak for such a big job. The scientists' frustration rose and rose until, in March 1990, Britain's Prince of Wales came to town. With his intense interest in conservation, Prince Charles gladly agreed to plant some vetiver personally. He thereby launched what is officially called "The British Council/Anambra State Project on Erosion Control," but is more commonly known as "Project Vetiver."
Thanks to the heir to the British throne, vetiver planting took off in earnest. "Prince Charles brought prestige to bear on the whole thing," noted Anthony Chigbo, secretary and project engineer of Project Vetiver. "We knew that the long strong roots would go deep and hold the soil in place, but we couldn't convince the average person. They believed that things are good only when they are costly!"
Within a year, field workers were reporting favorable results. Indeed, the Nigerian scientists and their British helpers now jointly predict that vetiver will significantly benefit the environment of Anambra.
Indian scientists reputedly introduced vetiver to some Ethiopian coffee plantations in the early 1970s. Today the grass is used particularly in Jimma and Kaffa provinces, where small informal nurseries of it are often seen along the roadsides. The Ministry of Coffee and Tea has promoted its use there for at least 10 years.
Ethiopians mainly use vetiver to protect the edges of contour drains, but the plant is becoming increasingly popular as an ornamental around houses. In addition, local farmers have found that the foliage makes
excellent mulch, and they say that (compared to napier grass, for example) it is easier to manage because it does not seed or take root when they spread it on their gardens or fields. Pine needles, which were traditionally laid on the floor during coffee ceremonies, are now commonly replaced by vetiver leaves. Vetiver straw is also gaining popularity as a thatch and as a stuffing for mattresses because it resists rot and lasts longer than other straws.
One advantage, widely believed in Ethiopia, is that Bermuda grass and couch grass cannot invade fields through a vetiver hedge. Indeed, the local Amharic name for vetiver means "stops couch grass."
Although vetiver is only now getting its first serious trials as an erosion control in Zimbabwe, Mauritian settlers in the Chiredzi area (hot, subtropical lowveld, 600–900 m altitude) have reportedly used it for years to reinforce the banks of irrigation canals. They also took it to the Chipinga area in the Eastern Highlands (warm, subtropical hill country, 900–1,200 m altitude), where a number of coffee planters use it to protect their terraces. Vetiver has also been planted across wet drainage flats (vleis), where it blocks the runoff, thereby keeping the soils moist for months into the dry season.
It has also been reported that tobacco farmers have found that hedges of vetiver around their fields keep out creeping grass weeds, such as kikuyu and couch.
Other African Nations
South Africa Vetiver is cultivated to a limited extent in South Africa and is used as a hedge plant, particularly in Natal where it is used mainly by Mauritian sugarcane growers and is commonly referred to as "Mauritius grass." A company formed for the purpose of putting in vetiver hedges has recently established trials throughout the country (see next chapter).
Madagascar Erosion is such a tremendous problem in Madagascar that farmers have rapidly come to recognize vetiver's usefulness. The grass is being planted, largely under a World Bank initiative. (The Bank's local representative is widely known as "Monsieur Vetivère.") Farmers have found that vetiver fits well with their traditional technique of torching their fields each year. Whereas most other erosion-control plants are destroyed, the vetiver is all but unaffected. Another reputed advantage is that vetiver does not harbor rats. More details are given in the next chapter.
Botswana In Botswana, vetiver (V. nigritana) is known to occur in the Okavango swamp area, but as of 1991 no erosion-control projects have been reported with either V. nigritana or the Indian species (V. zizanioides).
Malawi Vetiver is said to have been used in Malawi for 50 years to stabilize sugarcane.12
Mauritius Sugarcane growers on Mauritius rely on vetiver and take it for granted. "Any sugarcane grower in Mauritius will tell you that vetiver is used both for erosion control as well as some sort of barrier to prevent noxious weeds such as Bermuda grass from penetrating fields from roads," writes Jean-Claude Autrey, head of the Plant Pathology Division of the Mauritius Sugar Industry Research Institute. "The abundant root system of vetiver is ideal for this purpose."
Zaire The current situation is unreported, but in the 1950s vetiver was commonly found as an ornamental plant and as a border against erosion. Vetiver hedges were sometimes used to fix terraces in place on plantations of cinchona, for example.13
Central African Republic A solitary note in the Kew Herbarium Collection reports that vetiver is used for stuffing mattresses in the Central African Republic.
Rwanda For more than 30 years vetiver has been used in Rwanda's coffee plantations, apparently for protecting terraces.14
Gabon According to one report, the grass was planted along ditches and roadsides to conserve the soil and delimit field boundaries.15
Ghana Vetiver is a common hedge plant in Ghana. It is used particularly along the edges of roads, gardens, and cultivated fields. It is said to prevent a weed called "dub grass" (Desmostachya bipinnata) from invading. The leaves, in their young state, are used as cattle fodder.
Tunisia Apparently, Europeans introduced the grass into Tunisia, and it has been planted alongside pathways to conserve the soil.16
The Caribbean is one of the regions where vetiver is best known. Originally, "khus-khus grass" (as it is mostly called) was brought in from India. Today, it is commonly cultivated to avoid soil wash and the invasion of weeds. It is also an ornamental. The dried roots are sometimes used as an insect repellent, to protect clothes from moths, for example.
Vetiver has been used for erosion control on St. Lucia for at least 40 years (see next chapter). It is still widely valued, particularly on the wetter (southwest) side of the island. The foliage is harvested for mats and handicrafts. In earlier times, thatch was the main vetiver product. These days, however, the only places still employing it are said to be tourist facilities for visiting Americans.
Vetiver is often planted around buildings during construction. For example, the Hess Oil Company recently protected slopes around the schools it built near its refinery by using lines of vetiver.
Seemingly, it was the University of the West Indies17 that originally recognized vetiver's usefulness for soil conservation. As a result, the plant can now be seen all over Trinidad. Mainly it is planted alongside roads. Indeed, it is vetiver that stabilizes the embankments of many of Trinidad's roads.
At the university research station at St. Michaels, for example, vetiver's potential for stabilizing roadsides under the worst possible conditions can be seen. The road has been bulldozed into the side of the hill, and the resulting debris—subsoil, rock, and shale—is so bad it can hardly be called soil, yet the plants are growing actively and there is no sign of erosion.
Higher up the hills on this research station are found vetiver barriers established in old, eroding, "slash-and-burn" areas on slopes well over 100 percent (45°). Here vetiver must compete with jungle regrowth, heavy grass, and vines, but it has held its own and is doing an excellent job of holding these hillsides together.
These days, Trinidad's forest service is showing renewed interest in vetiver.18 In Maracas Valley, for example, it has planted fruit trees
behind vetiver contour barriers. On extremely steep slopes, as well as on terraces, one can see deep deposits of organic matter trapped behind the grass hedges. Mango trees are obviously benefiting (probably from the extra fertility as well as the deeper percolation of moisture); those away from the barriers are poor by comparison.
Because Haiti is the world's second biggest supplier of vetiver oil, the plant is very well known there. Unfortunately, however, in this country of impoverished soils, it has not been widely employed for erosion control. Its extreme robustness can easily be seen because it commonly occurs on the worst possible sites. Even when people are trying to produce vetiver roots commercially, they usually employ the least valuable ground, much of it so worn out that nothing else can survive.
However, only southern Haiti grows vetiver for oil. In the northern part of the country, people leave it in place and use it for soil conservation. "Vetiver works," notes one admiring Haitian. "The minute you remove it the banks fall down."
A good example of vetiver's abilities can be seen on the road from Port-au-Prince to Cap Haitien. Where it cuts through the hills, the embankments on both sides are lined with vetiver. The terrace effects have successfully stabilized these banks, an amazing feat considering their steepness and erodibility.19
Haitians like several of vetiver's features: it can withstand animals (which eat leucaena, for example), is easy to propagate, is drought hardy, and stays in place with minimum maintenance. Moreover, they point out that people can walk over vetiver without damaging it; doing that to leucaena generates a gap.
One widespread opinion that vetiver impoverishes soils has been debunked. Barrenness does occur in some vetiver areas, but hardly because of the plant. The hillsides had first been damaged to the point where farming was no longer possible, then turned over to goats, and only after the goats could find nothing else to eat did the farmers put in vetiver. For such sites vetiver was merely the last straw.
So far, not much vetiver has been used to stop farm erosion.
Vetiver is so common on Barbados that it is part of the landscape, and is much appreciated. A recent tourist brochure, for example, gushes over the plant:
Huge clumps of this bushy grass form continuous borders along most of the country roads in Barbados, providing a soil-erosion barrier around fields of its cousin, the sugarcane. This, however, is perhaps a lesser virtue to most people, the most gracious being the gorgeous smell of this rare fragrance of the tropics. The oil extracted from the roots is used to make a truly Caribbean scent—Khus Khus by Benjamins of Jamaica—available at all fine perfume counters.
The dried roots are also used to make unique souvenirs. These include: clothes hangers covered in khus-khus roots and bound in ribbons. (They give your cupboard a glorious, long-lasting scent, are thick and soft for hanging clothes on, and look very special.)
The leaves of the grass were used extensively to make thatch roofs in early days, but now only as a decorative, "typically tropical" feature. Examples can be seen at Southern Palms Hotel and Ginger Bay. In crafts, khus-khus grass is woven to make Dominican-style rugs at the IDC Handicraft Division. These can be bought by the square for wall-to-wall covering. Ireka, a Rastafarian girl from Mount Hillaby, uses khus-khus grass with balsam to make a whole range of distinct baskets which she sells at her shop at Pelican Village. Roslyn of Barbados uses the grass to make wall hangings and lampshades which are sold at Fine Crafts in the Chattel House Village, and at Articrafts in Norman Centre, Broad Street.
Vetiver can probably be found throughout tropical South America, but this is the part of the tropics where it is probably least known. Few South Americans are aware of its presence.
The plant is cultivated in the provinces of Chaco and Misiones and it is grown even as far south as Buenos Aires. Its roots are extracted and the essential oil used in perfumes. In Misiones it is employed in thatching ranchos.20
Although there has been no research on erosion hedges, the plant is known in Bolivia. Indeed, a project to explore this use has recently been initiated jointly by the Ministry of Agriculture and Campesinos and the Corporation for the Development of Cochabamba. Vetiver plants are now growing well in a nursery in Cochabamba, even though the altitude is 2,600 m. A "vetiver coordination center" is being established by the Organization for Environmental Conservation (AMBA).21
Brazil produces vetiver oil for its own internal markets and has probably been growing the grass for several centuries. Nothing specific on its use in erosion control has yet been reported, but a scientific paper22 reviewing vetiver in Brazil reported:
It is a plant of great utility. Its numerous and tangled roots bind the surface where there is danger of breaking the earth apart; its tufts of erect, perennial leaves serve as a fence, protecting crops against wind and dust storms. Later its collected leaves, which have practically no odor, can be used to make hats and its straw canes serve to cover cabanas and barns. Its roots, which have a strong odor, can be transformed into baskets or coarse mats that in certain regions are suspended in doors and windows and frequently wetted with water, perfuming the air and lowering the ambient temperature.
Vetiver can be found scattered throughout Central America, but few people recognize it or are aware of the job it does. Nonetheless, rows of vetiver are often seen where roadsides have been cut into hills.
Even before the initiatives in India began to arouse worldwide interest, plantings were increasing in an area of small farms and mixed agriculture southwest of San Jose. As a border to prevent erosion, the farmers say vetiver is better than lemongrass, which they had previously
used. Vetiver, they assert, tolerates more adversity, is more resistant to stem borers, lasts longer, requires less care, and (because it grows erect) interferes less with field practices.
The grass is commonly used as a hedge plant in the Meseta Central. It is also planted along the top of embankments to prevent rocks and dirt falling onto the road. An Indian group prepares the roots and sells them along with other local products, such as hats and baskets that they fashion out of local plants.
Guatemala once exported vetiver oil to the world. Although the trade stopped years ago, the plant still survives throughout the country. In a few places, it is even used as an erosion barrier. Engineers, for instance, have used it to protect road cuttings from washing out, and coffee planters have long relied on it for soil conservation. This has been mainly on plantations in the western coastal zones, especially in the Department of San Marcos.23
Some people (notably Indians in the hills) use vetiver leaves for thatch, for mulch to "break the rain" on seedbeds, and for bedding for pigs.
Recently, interest in vetiver has been renewed. The government and a private voluntary organization have formed a committee to coordinate vetiver promotion and research. Promising accessions have been located and were planted in six locations in October 1990. Only half of the plantings were watered, but, even though the dry season was just beginning, nearly all the plants survived.
Vetiver, of course, is a tropical species and would not be expected to grow in the temperate zones. Nonetheless, there are certain parts of North America where it survives and even thrives.
Vetiver has been in Louisiana for at least 150 years. The roots were once routinely relied on to keep moths out of closets during the summers (for which purpose, it is said, the roots remained effective for two years). There was also a small industry producing vetiver oil.
However, this plant, once so well known to Southerners, has been
essentially forgotten since at least last century. Nonetheless, field observations suggest that in all that time the neglected plants have not spread, but have remained where planted. Today, vetiver can be found along the banks of many bayous and on old plantations. Even where homesteads were razed or abandoned during the Civil War, vetiver still grows.
The plant is known in other parts of the deep South as well. Although present in Florida for probably a century or more, it has never been collected as an escape from cultivation.24 There was once a small vetiver oil industry in Texas, centered mainly in the area near Riviera. The plant was also grown along the Gulf Coast as well as in southern California before World War II.
Recently in Louisiana, exploratory trials using the plant as an erosion barrier have shown remarkable promise (see next chapter).
As related earlier, it was experiences in Fiji that stimulated the current rebirth of interest in vetiver. However, the grass is known to occur in many parts of the Pacific basin.
Several native species of Vetiveria grow in Australia (see Appendix B). All are found in the northern half of the continent. Recently, vetiver (the Indian species) has been tested with great success for its erosion-control abilities on highly erodible gullies near Brisbane. 25
The plant was apparently introduced to Fiji in 1907 and tested as a commercial crop before being let loose. Today, it is common in most parts of the islands and is sometimes used to bind rice bunds. Some people drink a tea made by boiling vetiver root in water. In some areas it has spread to populate roadsides and wasteplaces.26 It is not, however, considered a threat.
Its use in erosion control in the 1950s (as described in the introduction) has been largely forgotten. However, because of newly mandated requirements of the Environmental Protection Authority, a construction company recently used it to restrain erosion and runoff from a building site.
Other Pacific Locations
American Samoa In Aunu'u, the plant has been used around taro fields to choke out weeds.
New Zealand Some samples have been introduced to New Zealand, but so recently that no results have yet been recorded.
New Caledonia In New Caledonia, vetiver has been used extensively to prevent erosion on slopes, particularly along roads. It proved notably effective.27
Cook Islands Plants have been on the island of Atiu for at least 30 years, and probably much longer. They show no sign of any natural spreading, and in some former locations they can no longer be found. One particular plant, in a domestic garden, is known to be 28 years old but is still less than 1 m across.28
Vetiver, of course, is a tropical plant and should not be expected to occur in Europe. There are, however, several exceptions: one is France.
Vetiver was introduced to the south of France as a potential source of ingredients for the perfume industry of Grasse, on the Côte d'Azur. 29 It still exists there and survives the Mediterranean winter.
Recently, it has been tested as a barrier against soil loss, both there and on the slopes of the Massif Central.30