Vetiver’s positive response to being burned makes me wonder that over the centuries of being burned, it is now a ‘fire-climax’ plant. In the photo left, you can see a vetiver hedge burning in the tropics
The resulting regrowth from that fire shows the young growth either side of the ash-line left from the trash fire that was so densely shading the plants in the hedge. Obviously Vetiver, being a C4 plant needs as much sunlight as it can get for its regrowth, hence the regrowth on the outside edge of the old hedge. (right picture)
The picture on the below shows an established vetiver hedge in Ethiopia cut right down to the ground, to supply leaves for many purposes – forage: thatch; mattress stuffing; mulch; ceremonial purposes etc, but the regrowth from the complete plant base is obvious with no blank central line as with the burned hedge line. Was this ash-line a function of the heat of the fire? However, both the cut line and the burned line regrew within a month as complete hedges.