Black mondo grass 'Silver Mist' Green-Grey - Hardy plantIs it green or is it grey? The black mondo grass 'Silver Mist' (Ophiopogon japonicus) has unique, green leaves with a touch of grey. The black mondo grass remains small and is an eye catching ground cover for our garden. The plant is resistant to heat and drought and is evergreen. We can plant this plant all year round, provided temperatures don't go below freezing. The plant blooms in the summer with white and purple flowers. The plant does not