My brother likes to get gifts that he would like to play with himself. So, when he learned that there is such a thing as static grass, well guess what I received for Christmas.
I painted up a square of Styrofoam that has been lurking in a corner of the garage for half a decade waiting on exactly this opportunity. The tool came with a wee pouch of bright dark green fibers, so I tried those first in the wet paint, and then in Aileen’s Tacky Glue, acrylic matt medium and PVA. I can’t tell the difference between the results from Tacky Glue and PVA, but paint and matt medium did not hold nearly as well as those two.
Glancing at Gordon Gravett’s book on not-trees, I then tried a lighter layer atop the base layer. Again, I tried several adhesives – Dullcoat, Krylon Fixative and Krylon spray glue. They all seem to have worked about the same.
The results are somewhat uniform so far. As with most things in modelling, the key will be in layering, and Gordon’s fabulous book gives many suggestions for how to proceed.
Pembroke:87 
Which static grass unit did you get? Who’s fibres did you select?
For layering, try the cheapest unscented hairspray you can find on the shelf. You’ll be delighted at how well it enables layering and how long lasting (i.e. permanent) it seems to be. But it has the added benefit of being washable and removable, so you can salvage your fibres if need be.
It looks to be a no-name unit. Certainly there is no clear branding on the box. My brother also sent some Woodland Scenics material.
As for hair spray, Gordon Gravett recommends against it. Having said that, where do you get yours, and what brand do you use?