Planting Vetiver on a Slope : Video

This is a great explanation of a Vetiver project on a steep slope from 7thgenerationdesign.com
The site (make sure you check out the details) presents an interesting exercise in slope stabilisation similar to many Brisbane suburban slopes.
I may be  a bit over designed but the logic is clear. The climate is relatable as it's in Southern California -- although the plants are in full sun and the conditions are dry.
Note that the slope is covered in fill -- not a purely natural rise, so it will definitely slip and erode without intervention.
My suggestion would be to begin this process in sections and as each tier contour consolidates, create another hedge lower down.
I find that if you take your time by staggering your interventions, you get to understand the site better.
Also note the numbers used in hedge planting -- at  fist width apart. In this image above  there are around 200 plants. If you do your sums and compare the financial cost of other engineering options with the Vetiver system, the initial outlay in energy and money makes sense. Say, $150-200.
Now if you proceeded in sections over time and grew your own reserve division stock, we are talking el cheapo landscaping...You could, of course,  just purchase more slips as you go.
If your slope already contains bushes or trees, there may be a shade factor which would slow down the growth of  your Vetiver hedges. Don't rush to clear them as that obviously would serve to encourage erosion.
Leave any 'weeds' in too but mulch heavily over them for the same reason.
This video below from 7th Generation design explains the DIY. There are more videos of the project HERE.