Korean feather reed grass
This is wonderful grass that deservedly has an award of merit from the RHS.
Whether singly or en masse it's a delight in any landscape. It's easy to grow and tolerant of a wide range of conditions but does best in moisture retentive, well-drained soil in full sun or partial shade.
C. brachytricha forms a clump of glossy green, linear leaves that turn yellow in autumn. The narrow, fluffy, purple-tinged plume-like flowers open in late summer and early autumn, persisting into the winter.
It's a deciduous grass so should be left through winter and cut down to 15cm or so in early spring.