Growing vetiver hedges in temperate climates presents some different and even difficult problems from the wet tropics. In Northern New Zealand, vetiver hedges grow exceedingly well in the summer months, but during their winter dormancy they present a very different picture. Their excessive summer growth dries out completely and can present a fire hazard. In the wet tropics, vetiver hedges are virtually fire proof.
Photo 04 attached above, shows a vetiver hedge in winter dormancy, this hedge has been allowed to grow uncontrolled under a line of Phoenix Palms, as opposed to the next photo of the same hedge trimmed by previous owners of the property. If this dry hedge was set on fire or ignited by a bush fire, it would seriously damage these palms. If there were any buildings near a hedge like this they would be extremely vulnerable to being destroyed by fire. Under these conditions, vetiver hedges must be trimmed of excess summer growth, and the right time is as they enter their winter dormancy period.
The hedge shown in photo 08 was trimmed at the beginning of winter, is in the same district and was photographed on the same day as the hedge in 04. It has dried out but being clipped, presents no fire hazard. This hedge has not grown since it was trimmed months ago at the beginning of winter. The only way to prevent any fire danger from hedges in confined spaces, is to cut them back, but what do you do with the massive amount of leaf material harvested, and where do you get the labour to cut them?
In a temperate climate it is worth thinking at the outset that the hedges should be sited far enough away from buildings so that if they need trimming where there is no labour available, except the gardener, they can be safely burned.
In temperate climates where the hedges go through a long period of dormancy, it would be worth setting up a contractor to ‘harvest’ the hedges throughout the district at the beginning of winter, running the harvested leaves through a simple mulching machine, bagging the mulch or putting it through a stationary baler and selling it to Organic farmers or gardeners; using it as a pest-proof stuffing for pet’s mattresses; poultry farm litter and the essential pest proof straw for growing strawberries; even using it for handicrafts. This could be a lucrative business for a small contractor.
One major problem we have here in New Zealand with our large Dairy Industry, is handling runoff from dairy farms and preventing it from getting in to the drainage network. Vetiver hedges would be ideal for combating this problem, but, once again, when I talk to the Dairy farmers, they say, “harvesting the hedges is another job on the farm and we haven’t got the time or the labour for it” and when they are milking over 2,000 cows twice a day they don’t need any extra work. But for a ‘vetiver contractor’ the extra leaf cuttings he would get from dairy runoff would be massive. We just have to come up with ways of using this valuable product, and making it a worthwhile business proposition.
Any ideas?
The fire hazard period in Sardinia is from June to October, in this period there is the absolut ban on any free flame, even barbecues are strictly confined to domestic areas; afterwards the soil is more or less permanently wet therefore there is no fire risk watsoever. the dormancy period here starts in late November. I've never seen bushfires in any period besides the summer time, even the air bombardiers are here in Olbia airport until end September, afterwards they are repositioned to Rome or Sicily. Not a concern for us here definitely. But an idea could be this one : Infact chopped biomasses can be dried properly by heaters whose fumes and heat are conveyed in chambers that keep dry or dries out more chopped biomasses. If of interest I can gather more info, photos, etc on this matter, in any case, soon I'll publish more about the domestic heating with vetiver. With bigger heaters you could also heat (under the floor) stables, greenhouses etc...
ReplyDeleteMarco Forti
I will try to write more later but for now I will say that here in Santa Barbara we try to prune the Vetiver hedges in the late summer and early fall (Mid August - Mid September ) to reduce the amount of dry material in the hedge for fire concerns during the fall, and generate mulch material to cover any bare ground above or below the hedges in preparation for Winter rains which might begin as early as October , but usually begin in November . Enough good growing weather after the late summer pruning allows a thrifty regrowth of the hedge . Any drying up of the hedge in our Winter due to cold is not significant and occurs during our usual rainy period when fire danger is typically low . While the dried Vetiver mulch might represent a minimal fire hazard , we feel that the dense green pruned hedge is somewhat of a barrier to fire spreading and in many plantings we are irrigating the fruit trees and other plantings in between the Vetiver hedges , and this wets the mulch material offsetting the fire hazard.
ReplyDeleteDoug Richardson, California
Does anyone know any genotypes that would work for temperate climates (Chesapeake Bay)?
ReplyDelete