Ophiopogon planiscapus nigrescens
Black mondo grass has shiny black leaves and grows in tufts and mounts. New growth has a green hue then quickly turns to black.
An added bonus for this lovely plant are little bell shaped flowers of pink-pale violet-white and berries in black held aloft of foliage.
Grows to about 20-30cm
Grow in full sun to part shade in soil that doesn’t get parched with good drainage.