Plants forming dense clumps. Rhizomes pachymorph, neck 1--3 cm long. Culms to 5 m, to 1.5 cm in diam., pendulous; internodes to 30 cm, terete, lightly white-powdery at first, becoming yellow, longitudinal ribs very prominent, wall 1.5--2.5 mm thick; nodes with weakly prominent supra-nodal ridge, sheath scar prominent; branches 5--10, slender. Culm sheaths deciduous, far longer than internodes, distally papery and sparsely brown-setulose, apex narrow and linear, longitudinal ribs greatly prominent and red-brown, margins initially densely ciliate; auricles absent; oral setae scarce, erect, white-grey, to 3 mm; ligule ca. 1 mm, truncate or convex, glabrous; blade linear, revolute, glabrous, readily deciduous, margins usually serrulate. Leaves 3--5 per ultimate branch; sheath glabrous or apically slightly pilose; auricles absent or small; oral setae several, erect or spreading, yellow-brown, ca. 2--3 mm; ligule short, convex, to 1 mm; external ligule white-grey pubescent; blade narrowly lanceolate, to 7 × 0.7 cm, base cuneate, mid to dark green above, paler and proximally grey-pilose below, secondary veins 2--3-paired, margins spinescent-serrulate, transverse veins clear. Synflorescence unknown. Name from the Latin angustus, ‘narrow’.
Elegant, pendulous, very dense, slender culms and small, narrow foliage leaves. In its small leaves and prominent red-brown culm sheath veins it is similar to Fargesia nitida, but taller and more pendulous. The introduction from Wolong (illustrated here) is a very pretty bamboo with culms that become golden yellow, purple branchlets, pale unspotted culm sheaths with pale hairs, reddened branchlets and leaf sheaths, proximally densely pubescent lower leaf blade surfaces, and dark green leaves.
In the US seedlings from Waddick’s original Wolong introduction are cultivated. A second introduction identified as Borinda/Fargesia angustissima, from Pingwu, north of Wolong, to Holland in 1997 has denser, darker culm sheath hairs arising from dark spots, and somewhat thicker culms, and is the form usually cultivated in Europe under this name. That introduction is sometimes considered to be Fargesia ferax, although that is a bamboo that was described from near Kangding, on the border of Sichuan with Tibet, to the SW of Wolong. As with all recent introductions, the species identification of these introductions cannot be assumed to be correct.
Borinda angustissima was introduced to the west from Wolong, Sichuan by J. Waddick in 1989.