I would reserve it, and use it for other things.
For the tumbleweeds, depending upon scale, I'd either use those synthetic, green, scrubbing pads, pull and tease the material out into a loose ball, and spray either tan/sand, light gray, or a mix of the two. Leave loose, so you can just scatter them about the table, instead of basing them. Works for 15mm - 25mm/28mm scale, I suspect.
For larger figs, or larger tumbleweeds, on this side of the pond, you can get fibrous, low-cost, air filters for home furnaces. They're a jumble of either synthetic, or natural fibers, and here, are frequently green-blue in color. Pinch/cut off a bit, tease out if needed (probably doesn't in many cases), and use scissors to cut to shape. Paint, as above.
Simple, and very low cost for either method.
Enjoy!