Non-Native Plants

Non-native plant species are frequently found along river corridors in urban areas. This reflects the numerous potential sources of these species in urban areas, including domestic gardens, public parks, road and rail verges, abandoned land, and golf courses, and also the ability of rivers to collect, disperse and deposit seeds during spates.

Numerous non-native plant species may be present in the vegetation and soil seed bank, and a few of these can become invasive to the extent that they cause significant problems for native vegetation. The Environment Agency recently identified seven non-native plant species that have caused serious problems within rivers and along river banks across Britain: Himalayan balsam (Impatiens glandulifera), Japanese knotweed (Fallopia japonica), Giant Hogweed (Heracleum mantegazzianum), Floating pennywort (Hydrocotyle ranunculoides), Australian swamp stonecrop (Crassula helmsii), Parrot’s feather ((Myriophyllum aquaticum), Creeping water primrose (Ludwigia grandiflora).

American Skunk Cabbage (Lysichiton Americanus)

More info: DEFRA, Nature Locator

Buddleia (Buddleja Davidii)

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Cabbage-palm (Cordyline Australis)

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Canadian Fleabane (Conyza Canadensis)

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Cape Goosberry (Physalis Peruviana)

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Confused Michaelmas-Daisy (Aster Novi-Belgii)

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Fig (Ficus Carica)

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Floating Pennywort (Hydrocotyle Ranunculoides)

More info: DEFRA, Nature Locator

Foxglove Tree (Paulownia Tomentosa)

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Giant Hogweed (Heracleum Mantegazzianum)

More info: DEFRA, Nature Locator

Giant Rhubarb (Gunnera Tinctoria)

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Himalayan Balsam (Impatiens Glandulifera)

More info: DEFRA, Nature Locator

Hoary Cabbage (Hirschfeldia Incana)

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Italian Alder (Alnus Cordata)

More info: DEFRA

Ivy-leaved Toadflax (Cymbalaria Muralis)

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Japanese Knotweed (Fallopia Japonica)

More info: DEFRA, Nature Locator

Large Evening Primrose (Oenothera Glazioviana)

More info: DEFRA

Mexican Fleabane (Erigeron Karvinskianus)

More info: DEFRA

Monkeyflower (Mimulus Guttatus)

More info: DEFRA, Nature Locator

New Zealand Pigmyweed (Crassula Helmsii)

More info: DEFRA, Nature Locator

Parrot’s Feather (Myriophyllum Aquaticum)

More info: DEFRA, Nature Locator

Rape (Brassica Napus)

More info: DEFRA

Shaggy Soldier (Galinsoga Quadriradiata)

More info: DEFRA

Small Balsam (Impatiens Parviflora)

More info: DEFRA

Snowberry (Symphoricarpos Albus)

More info: DEFRA

Sweet Pepper (Capsicum Annuum)

More info: DEFRA

Tomato (lycopersicon Esculentum)

More info: DEFRA

White Melilot (Melilotus Albus)

More info: DEFRA

Yellow-flowered Strawberry (Potentilla Indica)

More info: DEFRA