Reynoutria multiflora in the EPPO region: addition to the EPPO Alert List
Why
Reynoutria multiflora (Polygonaceae) is recorded showing invasive tendencies in the EPPO region where it can occur in wooded habitats. The EPPO Panel on Invasive Alien Plants are seeking further information on any additional occurrences of R. multiflora in the EPPO region.
Geographical distribution
EPPO region: Hungary, Italy, Slovenia, Switzerland
Asia: China* (Anhui, Fujian, Gansu, Guangdong, Guangxi, Guizhou, Hainan, Hebei, Heilongjiang, Henan, Hubei, Hunan, Jiangsu, Jiangxi, Jilin, Liaoning, Qinghai, Shaanxi, Shandong, Shanxi, Sichuan, Yunnan), Democratic People's Republic of Korea, Republic of Korea, Japan
* = Native distribution
Morphology
Reynoutria multiflora is a perennial herb. Stems are twining. Subterranean part with root tubers black-brown, elliptic, ligneous (without rhizome formation). Leaves are individual, not clustered, ovate or narrowly ovate, 3–7 × 2–5 cm. Inflorescences terminal or axillary, paniculate, spreading, 10–20 cm. Flowers hermaphrodite. Perianth white or greenish; tepals elliptic. Achenes included in persistent perianth, ovoid, 2.5–3 mm.
Biology and Ecology
Stem fragments readily regenerate into viable plant. Buried stems root upon soil contact. R. multiflora seeds are viable. Hybridisation has been shown to occur between R. multiflora and R. japonica.
Habitats
In its native range, R. multiflora is recorded to occur on mountain slopes up to 3000 m above sea level. In the introduced range, R. multiflora is recorded to occur in wooded habitats, along forest edges and in urban and semi-urban areas and ruderal habitats.
Pathways for movement
International pathways include movement of the plant for horticulture. Plant propagules can be spread in garden waste and contaminated soil. Natural spread is by seed and stem fragments which can be spread by water in periods of flooding.
Impacts
Reynoutria multiflora can form a dense canopy which can cover native plants reducing their fitness. The increased biomass can cause tree branches to break. The almost 100 % cover, can reduce species richness and shade out native vegetation. R. multiflora has the potential to impact ecosystem services. It can damage historic heritage structures and have an economic impact due to management costs.
Control
Management measures can include physical and mechanical control measures. Control using herbicides is possible, however their use in certain habitats is restricted.
Sources
Cao DL, Zhang XJ, Qu XJ & Fan SJ (2023) Phylogenomics, divergence time estimation, and adaptive evolution in the Polygonoideae (Polygonaceae). Journal of Systematics and Evolution 61(6), 1004-1019, https://doi.org/10.1111/jse.12946
Galasso G, Conti F, Peruzzi L, Alessandrini A, Ardenghi NMG, Bacchetta G, & Bartolucci F (2024) A second update to the checklist of the vascular flora alien to Italy. Plant Biosystems 158(2), 297–340, https://doi.org/10.1080/11263504.2024.2320129
Jousson A, Rosselli A, Beenken L, Frey D, Pezzatti GB, Conedera M, Jutzi M, Brånstrand I & Marazzi B (2025) Biological traits and reproduction of two emerging alien lianas in Southern Switzerland. Botanica Sudalpina, 21 November, Bellinzona, Switzerland.
Jousson A, Rosselli A, Conedera M, Marazzi B, Pezzatti GB, Jutzi M, Durini M & Frey D (Submitted) One step beyond the garden fence: Naturalization patterns of two ornamental alien climbers Fallopia aubertii and Reynoutria multiflora in southern Switzerland.
Li A & Park C (2003) Fallopia Adanson. In: Wu Z, Raven PH (eds) Flora of China, Vol. 5: Polygonaceae (Ulmaceae through Basellaceae), pp 315-319. Accessible online through eFloras - Flora of China. http://www.efloras.org