Vetiver Symbiosis

[Dave Riley]

Tho Ngo's work in Vietnam (near Hanoi)  pairing Vetiver with fruit trees  and vegetables plantings is an exciting project.

Tho's hypothesis is that Vetiver 'wicks' moisture up to the accompanying plant's roots....even when both plants are planted in the same hole.

In Thailand, as elsewhere (like my own garden) , vegetable beds are laid out  with similar attributes in mind by bordering them with Vetiver hedges.

As you can see (click on image to enlarge), the Vetiver is also cut for mulch.

Vetiver roots -- which can go down 2 metres -- are also sponsoring of rich microbial activity and carbon sequestration. As well the stems and scented leaves offer various means of protecting companion-ed plants from bugs.

[Dave Riley]

For those interested an updated users manual for Vetiver is freely available online.HERE.
Full of DIY approaches and tips for applying Vetiver to your land.
It begins with a discussion about sheet erosion and explores the many uses and properties of the grass..

ATTRIBUTES:

When planted correctly (i.e. close together), it will quickly form a dense, permanent hedge.
•Has a strong fibrous root system that penetrates the soil verti-cally and binds the soil to a depth of up to 3 meters and can withstand the effects of tunneling and cracking.
•Is perennial and requires minimal maintenance.
• Is practically sterile - it produces no stolons or rhizomes, it seeds are sterile . It will not become a weed.
• Has a crown that is below the surface, which protects the plant against fire and overgrazing.
•Has sharp leaves and aromatic roots that repel rodents, snakes, and similar pests.
• Has leaves and roots that have demonstrated a resistance to most diseases.
• If managed correctly it makes an excellent fodder....
• Is both a xerophyte and a hydrophyte, and once established, vetiver grass can withstand drought, flood, and long periods of waterlogging.
• Will not compete with the crop plants it is used to protect, and in fact, vetiver grass hedges have been shown to have no negative effect on - and may often boost - the yield of neighboring food crops.
• It has associated nitrogen processing mycorrhiza, that explains its green growth throughout the year.
• Is cheap and easy to establish as a hedge and to maintain—as well as to remove if it is no longer wanted.
• Will grow in all types of soil, regardless of fertility, pH, or salinity, including sands, shales, gravels, and even soils with aluminum toxicity.
• Will grow in a wide range of climates and is known to grow in areas with average annual rainfall between 200 and 6,000 millimeters and with temperatures ranging from a ‘flash frost” of -14º to +55º Centigrade.
• Is a climax plant; therefore, even when drought, flood, pests, disease, fire, or other adversity destroy all surrounding plants, the vetiver will remain to protect the ground from the onslaught of the next rains.

[Andrew Cumberland]

Thanks!  I'll also send Paul a copy.  

[Lily]

Dave, having been inspired by your enthusiasm for it, I have obtained some vetiver to begin reinforcing the flimsy garden-edging terraces on my steep (30 degrees maybe?) baby food forest. I’ve read through the vetiver system handbook and I feel I’ve got a good handle on it all, but I was wondering how wide I should expect a mature vetiver hedge to grow? Will it keep bulking out if I’m cutting it for mulch and so it doesn’t get high enough to shade things around it? And will I be able to keep it narrow by chopping off the downhill edges for use as planting slips, or will I need to dig up the whole clump to divide? Thanks!

[Dave Riley]

• garden-edging terraces on my steep (30 degrees maybe?):  with that geography, make sure you plant the Vetiver slips close together. Like fist apart. 10cm. Along the contour. Suppress other impulses, especially to reduce your numbers. You want a hedge ASAP. So remember -- 1 metre of hedge will require around 8-10 slips.Farther apart and they'll take so much longer to meet up.
  
• how wide I should expect a mature vetiver hedge to grow?: You mean after 100 years? If they get too wide (as the manual suggests) just dig a trench along one or both sides.If you grab a handful of tillers bunch them up then imagine that x number expanding.These images of Vetiver landscaped presume maintenance. The oldest clump I've dug up was 4 years old and that was not a huge circumference.
• Will it keep bulking out if I’m cutting it for mulch: Yes. Just like any lawn and depending on the soil's fertility, moisture and the like. Cutting encourages more tillers to grow, but  the inside stems will tend to  die back as the plant turns in on itself.
• so it doesn’t get high enough to shade things around it?: 1.8-2 metres is the average height here. That's shady perhaps. But you cut it, right? You cut it for mulch. Cut is to around 30cm high.Keep it trimmed like a hedge is trimmed to shape. Use a sickle or a brushcutter. Scissors or secateurs.    At the moment I have no clump more than a metre tall, because I'm always hungry for mulch. The drought also has slowed growth.
  
• will I be able to keep it narrow by chopping off the downhill edges for use as planting slips : I wouldn't fret too much about its width. As your forest grows and the shade above rises the Vetiver will slow down. This isn't Gamba or Pampas grass.  The trick with Vetiver is divide it early in its life as the challenge increases with the multiplication of tillers. Chopping off pieces, while not impossible is also strenuous. If you want more slips, grow some Vetiver elsewhere in a 'nursery' bed and divide that clump at 15-20 tillers.That makes the Vetiver lifestyle so much easier. Just replant a tiller or two in thes ame spot for future stock. Fiddling with your hedge on the contour too much can only leading to undermining its integrity. Let it do its work.
• will I need to dig up the whole clump to divide? ; If you want to  do that, follow this dig up & divide DIY. But you won't need to. I have a bent crowbar to prove how keen the roots are to hang onto the earth. To kill off a clump, just cut it very very low and do the same if there is any regrowth. Same as your lawn.

Check these resources:

• My discussion contributions here on BLF. Just enter the search word 'Vetiver'.
• My own project and nursery site where I'm trying to build up a lot of information drawn from my own  activities: Vetiver Community Project.As I work with various folk I'm exploiting their feedback. (Photos of your experience would be much appreciated).
• I'm now on Gumtree.