Kingdom:   Plantae
(Unranked):        Angiosperms
(Unranked):        Monocots
(Unranked):        Commelinids
Order:       Poales
Family: Cyperaceae
Genus: Carex (Sedge Family)
Species: C. oshimensis
Form name: Carex oshimensis ‘Evergold’
Synonym: Carex morrowii ‘Aureovariegata'
Common name: Oshima sedge, Variegated Japanese Sedge, Japanese Sedge grass, Oshima kan suge, Everbrite, Old Gold, Variegata.

The sedge Carex oshimensis is native to the Japanese main island of Honshu where it is common in dry woods and rocky hillsides. This ornamental form was selected long ago by Japanese gardeners who have always had a special love for plants with variegated foliage.
This evergreen Japanese sedge forms a low cascading clump of thin blade-like leaves. The weeping, golden-yellow leaves are attractively edged dark green and form a dense tussock that spreads out slowly by short underground rhizomes. It will reach a height of > 50cm and a spread of >50cm. It has insignificant brownish flowers spikes on 15.2 cm triangular stems.
This sedge grows best in moist but well-drained soils. Many types of sedge are wetland plants, but Oshima sedge is not.

Photographed at Pukekura Park, New Plymouth.
Carex oshimensis ‘Evergold’ Oshima sedge -001.JPG

Carex oshimensis ‘Evergold’ Oshima sedge -002.JPG

The insignificant seed heads. October.
Carex oshimensis ‘Evergold’ Oshima sedge -004.JPG

The underside of a leaf.
Carex oshimensis ‘Evergold’ Oshima sedge -003.JPG 

Thanks to Wikipedia for text and information: https://creativecommons.org/licenses/by-sa/3.0