Since the steel grass is a bold, dark green, I wanted a little contrast with the inner leaves. I choose a variegated leaf. There are several varieties to choose from.
Pittosporum is a good choice, because it is available all year round. The leaves have a thicker, waxy feel and are a slightly rounded leaf.
You can insert the sharpened points of the bottom of each leaf directly into the foam like you did with the lily grass.
Another smaller leafed greenery is variegated boxwood. It has a more pronounced yellow tones to the leaves.
Keep in mind that the goal is to cover up the inner foam - NOT to conceal the lovely looping of the steel grass.
Keep the leaves tight and inserted deeply, allowing the framework of the steel grass to clearly remain visible on the outer edges.