Hmmm.... well, you've all given me a lot to think about. I'll take some pictures today to post. The area I want to stabilize is too steep for rip-rap or geotextile&soil nails. The problem is that the hillside is constantly being undercut by high water flows in the creek below. At each high flow, the creek chews out another foot at the bottom, and the entire steep slope above then slides down - carrying trees and plants with it. Eventually it will stabilize of course. But it will be really ugly for 100 years if it does what I think it will do.
It gets more complicated because I can't get right up to the site to work on the steep slope. It's across a creek.... That's what got me start thinking along the lines of some kind of blob cannon that would shoot a cup-size blob of concrete or something about 50 feet. It would be a sort of long process. Need to build up a footer at the far edge of the creek first, and then rise up along the wall from there.
rScotty