Hi Terry, I believe blood grass is meant to be an aquatic plant, or at least the nursery near me sells it as that. When I saw that, I decided to plant it into coir mixed with a bit of potting mix, and also try to keep it moist by using pots that don't have drainage holes, or sitting in water. Also, I don't tend to keep them in full sun, more dappled sunlight, cos Summer here is brutal.
That one I've shown is kept in the shade house on the Eastern side of the house, so only gets a couple of hours of good light every day.
Edit: I suspect if it got more light it wouldn't grow so tall...that's something I'll look into eventually.