Fallopia sachalinensis

(F. Schmidt) Ronse Decraene

Bot. J. Linn. Soc. 98: 369. 1988.

Common names: Giant knotweed
Basionym: Polygonum sachalinense F. Schmidt Mém. Acad. Imp. St.-Pétersbourg Divers Savans 9: 233. 1859
Synonyms: Reynoutria sachalinensis (F. Schmidt) Nakai Tiniaria sachalinensis (F. Schmidt) Janchen
Treatment appears in FNA Volume 5. Treatment on page 542. Mentioned on page 541, 543.

Herbs, perennial, rhizomatous, 2–4(–5) m. Stems usually clustered, erect, sparingly branched, herbaceous, stiff, glabrous, glaucous. Leaves: ocrea persistent or deciduous, brownish, cylindric, 6–12 mm, margins oblique, face without reflexed and slender bristles at base, otherwise glabrous or puberulent; petiole 1–4 cm, glabrous; blade ovate-oblong, 15–30(–40) × 7–25 cm, base cordate, margins entire, glabrous or scabrous to ciliate, apex obtuse to acute, abaxial face minutely dotted, glaucous, with hairs along veins distinctly multicellular, 0.2–0.6 mm, tips acute to acuminate, adaxial face glabrous. Inflorescences axillary, mostly distal, erect or spreading, paniclelike, 3–8 cm, axes puberulent to pubescent; peduncle 0.1–4 cm or absent, puberulent to reddish-pubescent. Pedicels ascending or spreading, articulated proximal to middle, 2–4 mm, glabrous. Flowers bisexual or pistillate, 4–7 per ocreate fascicle; perianth accrescent in fruit, greenish, 4.5–6.5 mm including stipelike base, glabrous; tepals obovate to elliptic, apex obtuse to acute, outer 3 winged; stamens 6–8; filaments flattened proximally, glabrous; styles connate basally; stigmas fimbriate. Achenes included, brown, 2.8–4.5 × 1.1–1.8 mm, shiny, smooth; fruiting perianth glabrous, wings flat to undulate, 1.8–2.2 mm wide at maturity, decurrent on stipelike base to articulation, margins entire. 2n = 44, 66, 102, 132 (Japan, Korea).

Phenology: Flowering Jul–Oct.
Habitat: Disturbed places
Elevation: 0-500 m


V5 1108-distribution-map.gif

Introduced; B.C., N.B., Nfld. and Labr. (Nfld.), N.S., Ont., P.E.I., Que., Calif., Conn., Del., Idaho, Ill., Ky., La., Maine, Md., Mass., Mich., Mont., N.J., N.Y., N.C., Ohio, Oreg., Pa., R.I., Tenn., Vt., Va., Wash., W.Va., Wis., Asia (Japan), introduced in Europe.


Fallopia sachalinensis was introduced as a soil binder and garden ornamental. Like F. japonica, it spreads aggressively and has been declared noxious in California, Oregon, and Washington. It hybridizes with F. japonica, yielding F. ×bohemica. The mid-stem inflorescences of F. sachalinensis usually are shorter than the subtending leaves.

Selected References


Lower Taxa

... more about "Fallopia sachalinensis"
Craig C. Freeman +  and Harold R. Hinds† +
(F. Schmidt) Ronse Decraene +
Polygonum sachalinense +
Giant knotweed +
B.C. +, N.B. +, Nfld. and Labr. (Nfld.) +, N.S. +, Ont. +, P.E.I. +, Que. +, Calif. +, Conn. +, Del. +, Idaho +, Ill. +, Ky. +, La. +, Maine +, Md. +, Mass. +, Mich. +, Mont. +, N.J. +, N.Y. +, N.C. +, Ohio +, Oreg. +, Pa. +, R.I. +, Tenn. +, Vt. +, Va. +, Wash. +, W.Va. +, Wis. +, Asia (Japan) +  and introduced in Europe. +
0-500 m +
Disturbed places +
Flowering Jul–Oct. +
Bot. J. Linn. Soc. +
Weedy +  and Introduced +
Reynoutria sachalinensis +  and Tiniaria sachalinensis +
Fallopia sachalinensis +
Fallopia +
species +