Selecting the Correct Vetiver Grass for Soil Conservation Projects

Friday, August 16, 2013


In a recent discussion on The Facebook Vetiver Grass Network, a member from Jamaica was concerned about finding the correct vetiver grass to propagate for a local project. The register of verified vetiver growers in The Vetiver Network International does not include any sources in Jamaica. Without a trusted source, the selection of planting material can be tricky.

Dale Rachmeler, Vetiver Network Director for Sub-Sahara Africa replied in that discussion:
There are at least 11 species of vetiver and lots of cultigens and cultivars. Only one of the species, Chrysopogon zizanioides, is sterile (actually it sets infertile seed very infrequently) - so no viable seeds in C. zizanioides. Its root system is vertical in nature made of a mass of fine roots growing vertically downwards originating from the crown of the plant that is usually 4-6 inches below the surface of the ground,

The flower stems and leaves also emerge from the same crown that has nodes that encircle the crown. New crowns can be formed on the nodes of on the flower stem that appear for up to 12 inches above ground. These nodes are activated when soil accumulates behind hedges and the nodes are covered by that accumulated soil. These nodes then produce new plants that have the emerging crowns and this is the mechanism by which vetiver hedges can protect the front side of the accumulated soil and create a vegetative barrier that rises more or less vertically with the increased accumulation of soil (the creation of natural terraces).

If farmers or other locals see what they think is vetiver encroaching into their fields then it is definitely not C. zizanioides. All the other species of vetiver are seeded and can be invasive. For example, on the African continent you have C. nigritana which is found all over the place in isolated clumps that were formed from seed that is blown mostly by the wind. It has also been used for vegetative barriers but has a much smaller root mass than zizanioides (let's say by a factor of 3-5). For most people it is very difficult to tell the difference between these two species as they look very similar above ground. There is a slight difference of color of the flowers, and the spacing between the flowers on the stem is slightly different. The root color for nigritana is browner than for zizanioides which has a lighter color.

C. zizanioides has spread around the world mainly for its essential oil in the roots (1800s to 1900s) and recently since 1990, mainly because the Vetiver Network has taken it to over a 100 countries for soil and water conservation. In this modern era, DNA typing is available and affordable and is the only definitive way to make sure you have zizanioides. Once you have it, you are set to go and since you can multiply a clone when you grow it in a nursery.

The most practical and reliable way is to know the origin of the nursery material. There is more information on The Vetiver Network International dealing with the species variation and the distinctions between them. A collection of African vetiver is held in South Africa and is being tested for DNA. India holds a collection of all species and they mainly do breeding work for oil bearing zizanioides cultigens. Please continue to ask questions and be curious about vetiver. In the end I think you will find that it is a very worthwhile issue to get involved with.
The plants from Agriflora Tropicals, available to the USA and its territories, at the Agriflora Tropicals store, are certified to be of the non-invasive type by the US Department of Agriculture. In other countries, checking the list of verified sources on The Vetiver Network plant suppliers page is the best first step. Read more about the vetiver plant in "The Plant" section of this blog.

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