Ophiopogon planiscapus 'Nigrescens' 
A low growing perennial that can be used in a similar way to grasses, very dark foliage creates a nice tight clump from which small flower spikes are produced with small purplish flowers, these are then followed by black berries.
Prefers a moist soil.
Hardy, evergreen grass
The plant will be supplied in a 2 litre pot