Introduced from mountains of Japan and Sakhalin Islands. Stalk bases fused and sheathing. Main stems erect, often arched near top, simple to minimally branched, grooved, thick, hollow , weakly woody, swollen at nodes, usually reddish-brown at maturity. Twigs often zigzag slightly from node to node. Tips acute to acuminate.
Bases truncate to tapered.
Stems sometimes pubescent, especially new growth. Leaves lanceolate , 10-20 cm long , often with short hairs on veins, margins, and lower surfaces. Bases slightly heart-shaped to tapered. Tips tapered, acute to acuminate. Leaves broadly lanceolate, 15-35 cm long .