Ornamental grasses often have attractive winter characteristics that should be preserved through the colder months. But the weather can leave them looking a bit ragged.
Since many grasses keep their showy flower stalks through the winter, wait to prune until late winter or early spring, just prior to new shoot growth.
In north and central Florida, prune ornamental grasses in February and March. In South Florida, you may wish to cut back or trim ornamental grasses in January or February.
For deciduous grasses like some Miscanthus, the old foliage may be completely removed with a chainsaw or hedge shears. For evergreen grasses like Fakahatchee grass, the ragged, dead leaves can be removed by combing the grass with a pitchfork.