Years ago - at the Nettetal snowdrop event - I bought a special cultivar of Ophiopogon planiscapus 'Nigrescens', which is much smaller and grows a lot denser. The flowers are almost unnoticeable, but the general aspect is lovely. Sadly I can't for the life of me remember who I purchased it from. And I haven't found anyone so far who could name the cultivar or supply it.
Though a slow growers, these plants (fortunately I bought 3) have done very well. (When it stops raining, I'll try to take another photo as this one is a year old.) I dream of underplanting a Cercis Canadensis 'Forest Pansy' with these. But it looks as if I'm going to have to propagate them myself, so getting a dense carpet of them will take me years...
Can any of you name the cultivar?