If it's Molinia caerulea 'Variegata' it's a cool season grass, and should regenerate foliage quickly.

thanks
I thought as much but , as we have never had 2 uses of it in the same year. (I use it for flower decoration ) I have never actually seen it regrow before.
Might it be a good idea in other years to deliberately cut part of the crop down early so as to get a succession of cuttings for the course of the summer? (instead of the glut I normally have)?

In general, cool season grasses may be cut back 2-3 times during the year, and will respond with new growth. In my climate, I can get regrowth twice in the spring and at least once in the fall (I have cool springs and warm falls.).

They go fully or semi-dormant during the hottest and coldest seasons, so plan your cuttings to occur just prior the the cool seasons in-between.