Static grass would be fine, or, even easier, and great for this scale, a 'hairy mat' sheet of grass. This is basically static grass already in place, on a roll. It would give the appearance, in 1/72nd scale, of grass about 8 inches tall, maybe a bit taller. Also, there is a 'meadow' grass product available, in various colurs, which would be about 18 inches tall or more in this small scale. Alternatively, use the 'hairy mat', and cut lengths of bristles from old household decorating paint brushes, and make 'clumps', planted into the base, and paint with watercolour paints if required. The products mentioned above are available from most model shops, and especially model railway outlets. You'll find them in the 'Scenics' sections normally.
At the same place, you'll find 'foliage', for groundcover or for making trees, which is idela for makeing scrub, bushes etc. It's a sort of fabric tuft, which you pluck apart as needed, and just fix down with PVA or similar.