Best grown in rich, humusy, medium moisture, well-drained soils in full sun to part shade. Prefers consistent moisture in soils which do not dry out. Not reliably winter hardy in USDA Zone 5 and the northern part of USDA Zone 6 where it should be sited in a protected location. Although rhizomatous, it spreads very slowly. Evergreen in warm winter climates, but foliage may depreciate considerably in St. Louis winters.
'Nigrescens' is a mondo grass cultivar which is noted for its purplish-black leaves, bell-shaped pink flowers and globular bluish-black berries. Unusual foliage gives rise to additional common names of black mondo grass and black lilyturf for this cultivar. Somewhat suggestive of liriope, this is a stemless plant which features slowly spreading clumps of narrow, linear, grass-like, basal leaves (to 1/4" wide) typically rising 6-9" tall. Foliage is a very dark purple and in many light situations appears black. Racemes of bell-shaped, light pink flowers appear on dark stems rising slightly above to slightly below the foliage in summer, providing excellent contrast with the dark leaves. Flowers are followed by glossy dark purple berries. Synonymous with and sometimes sold as O. p. 'Ebony Knight' and O. p. 'Arabicus'.
No serious insect or disease problems. Slugs and snails may be occasional visitors. Winter hardiness in the St. Louis area is a concern.
Border foregrounds, rock gardens. Specimen, group, small area ground cover or path edger.