I have an embankment that is hard clay. I am trying to find the type of grass seed or mulch that they put down at construction sites and alongside roads to make the grass grow (The green stuff they spray). Does anybody know what this is actually called or where I could find it?

What you are referring to is called hydro-seeding or hydromulching. I don't think it is available for purchase at a HDepot or Lowe's.

The closest product available to consumers is a grass "patch" mix that is similar in concept, but is generally used for small lawn areas.

Hiring a hydroseeding contractor may be the way you want to go. They can prep your clay soil as well as seed.

There should be small companies in your area that specialize in residental work.

For general info, go to:

www.aboutus.org/HydroSeeding.org

Have you considered planting a groundcover
(Vinca, Pachysandra)?

What about small spreading shrubs such as the junipers. Yes, you'll have maintenance and watering, but won't have to cut the grass.

Good luck!