Scleranthus biflorus

Adapting to the smallest reliefs of the rockery, Scleranthus biflorus, also known as Canberra Grass or Knawel, forms small evergreen mounds that slowly spread into vibrant green carpets. Native to the mountains of Australia and New Zealand, capable of surviving 6 months under a blanket of snow, this alpine perennial blooms in early summer with tiny yellow-green flowers. This plant forms a precious setting for spring-flowering bulbs and creeps between the stones of walls, in cool, well-drained soil.

Scleranthus biflorus is a relative of the carnation, belonging to the same family as the Caryophyllaceae. This montane perennial forms persistent cushions that do not exceed 15cm (6in) in height, but can form 60cm (24in) diameter mats after 5 years, conforming to all reliefs. It bears many small narrow and tough leaves of a beautiful spring green, resembling a carpet of moss. The flowering takes place in early summer, in May-June, in the form of tiny two-pointed yellow-green flowers. Under favourable growing conditions, this plant can live for years.

Its vibrant green cushion-like appearance makes Canberra Grass a popular plant in Japanese gardens, alpine rockeries, flower beds, pots, and borders. It is often associated with spring-flowering bulbs, as it fills empty spaces once their flowering is completed. This relatively easy-to-grow plant is decorative with its unique and characteristic moss-like appearance, and is remarkable as a ground cover.

This perennial owes its name, Scleranthus, to its tough and resistant calyx that tends to persist on the plant.