Plants forming dense clumps. Rhizomes pachymorph, neck 2--5 cm long. Culms to 2.5 m, to 1 cm in diam., pendulous; internodes to 15 cm, terete, lightly blue-grey waxy at first, becoming yellow green to deep red-purple, smooth, glabrous, wall thick; nodes lightly swollen, supra-nodal ridge distinct, sheath scar thin; branches initially (3)-5-(7), strong. Culm sheaths deciduous, much shorter than internodes, triangular, tough, smooth, light purple green, usually glabrous or with sparse to dense red or light brown hairs, apex narrow, margins distally densely c. 3mm ciliate; auricles small, erect or reflexed; oral setae few to several, erect, 2-6mm; ligule to 3 mm, fimbriate to 3 mm, tomentose; blade triangular, lightly pubescent, usually erect, reflexed towards base of culm, very persistent, margins ciliate. Leaves 1--6 per ultimate branch; sheath distally lightly tomentose, external margin ciliate; auricles absent or very small; oral setae absent or very few, erect or curved, ca. 1-3 mm; ligule convex, to 1 mm, tomentose, ciliate to 1 mm; external ligule white-ciliate to 2 mm; blade broadly lanceolate, to 10 × 2.0 cm, base rounded, adaxial glabrous, abaxial glabrous or lighly pilose; secondary veins 3-4-paired, margins distally spinescent, transverse veins distinct. Synflorescence a racemose panicle supported by leafy bracts, with spikelets of several long-mucronate florets. Name nepalensis Latin, ‘from Nepal’.
This species is characterised by the absence of auricles or oral setae on the leaf sheaths, glabrous culm sheaths, and the broad leaf blades, fewer in number than in T. spathiflorus and T. crassinodus, especially in winter, when just two very pendulous blades are commonly seen. The culm nodes are not as prominently swollen as those of T. crassinodus.
Introduced into the UK in 1983 from the Upper Dorandi Khola (Schilling 2616), and in 1985 from Nyalam in Tibet near the border with Nepal.