Giant Borinda

Borinda grossa (T.P. Yi) Stapleton, Edinburgh J. Bot. 51(2): 288. 1994

 Synonyms: Fargesia grossa T.P. Yi, J. Bamboo Res. 2(2): 35 (1983); Yushania grossa (T.P. Yi) Demoly   

Plants forming dense clumps. Rhizomes pachymorph, neck to 10 cm long. Culms  to 8(-12) m, to 3 cm in diam., nodding to pendulous; internodes to 35 cm, terete, green, becoming orange-yellow, with white wax mainly in apical ring at first, elsewhere wax light and deciduous, glabrous with no bristles or hairs, longitudinal ridges very prominent, walls relatively thin, cavity large; nodes not swollen, supra-nodal ridge distinct but not raised, sheath scar prominent; branches initially (3)-5-(7), central stronger. Culm sheaths deciduous, similar in length to internodes, thick, initially bright green or reddish apically, often reddish lower down and basally pale, with lightly waxy base and margins, scattered orange-red setae though basally glabrous but with a dense narrow ring of upright reddish hairs around the base, apex broad, margins initially prominently ciliate; auricles absent; oral setae several, erect or wavy, brown, to 15 mm; ligule level, to 5 mm, ciliate, glabrous; blade linear, very long, wavy, glabrous, horizontal to reflexed, green, quite persistent, margins usually glabrous. Leaves 3--5 per ultimate branch; sheath pale green, glabrous, margins glabrous; auricles absent; oral setae several, wavy or erect, stout, basally light brown, apically white, ca. 4--10 mm, glabrous; ligule truncate, 1-2 mm, glabrous; external ligule shortly white-ciliate; blade narrowly lanceolate to lanceolate, to 18 × 1.6 cm, basally cuneate, fresh mid-green, abaxially glabrous but proximally pubescent, secondary veins 3-5-paired, margins spinescent-serrulate, transverse veins distinct; petiole abaxially pubescent. Name grossa Latin for large, for the overall stature.

Recently found in cultivation in the UK (Youdale 2026), with moderately sized culms. The long, glabrous internodes bear little wax except for an apical ring below the node. Foliage leaves are of intermediate size and glabrous, with no auricles but tall, smooth oral setae. Culms soon glossy dark green, becoming yellow, and lacking the blue wax of Borinda papyrifera or the hairs of Borinda macclureana. Hardiness in cultivation not yet properly assessed, and maximum size unknown.

The species was initially described from a collection made at 2600m in Cona County, Tibet, which was probably within about 2 miles of Arunachal Pradesh, as the valley bottom at the border is only 200m lower at 2400m. The border with Bhutan would be about 9 miles to the west. Found from Central Bhutan to Western Arunachal Pradesh, and only likely to grow in small areas of Tibet quite close to the southern border. It flowered gregariously across its range from about 2005.

Many introductions of Borinda macclureana have been misidentified as Borinda grossa or called ‘Giant Borinda’, and several introductions of Borinda papyrifera reach similar ‘Giant’ stature.

Photos above are all from plants growing in Bhutan, where the culms are used for a variety of purposes, notably matting and fencing, and are both cultivated and extracted from the forest, where the bamboo stands constitute an economically important non-timber forest product.

Youdale, J. (2026). In search of Borinda grossa. Bamboo Society of GB Newsletter Oct 2026.

 Several introductions of Borinda grossa were apparently made from a few areas of Arunachal Pradesh by plant collector Keith Rushforth on trips in 2005-8, but only one collection number (KR8623) is associated with the few known surviving plants, which were all raised from seed. That collection number refers to a locality at 3,200m which seems most likely to have been in the area around Mandala Top near Dirang, West Kameng District, about 8 miles from the border with Merak and Sakteng Gewogs in East Bhutan.