Bernard Castelein / Cabbage white (Pieris brassicae) covered in dew droplets, on Knotweed (Polygonaceae) flower. Peerdsbos, Brasschaat, Belgium. September.

Dave Bevan / Moorhen (Gallinula chloropus) feeding chick in a pond covered with Water smartweed (Persicaria amphibia), Ceredigion, Wales, UK. July.

Dave Bevan / Pair of Moorhens (Gallinula chloropus) feeding chicks in a pond covered with Water smartweed (Persicaria amphibia), Ceredigion, Wales, UK. July.

Dave Bevan / Little grebe (Tachybaptus ruficollis) preening, surrounded by Water smartweed (Persicaria amphibia), Ceredigion, Wales, UK. July.

Nick Upton / Donje Bare glacier lake fringed with Bulrushes (Typha latifolia), Alpine dock / Monk's rhubarb (Rumex alpinus), Heartleaf / Giant oxeye daisy (Telekia speciosa) and dense mixed forest, Zelengora mount...

Dong Lei / Noble rhubarb (Rheum nobile), Mount Namjagbarwa, Yarlung Zangbo Grand Canyon National Park, Tibet, China.

Jussi Murtosaari / Water smartweed (Persicaria amphibia) in flower, Jyvaskya, Keski-Suomi, Lansi- ja Sisa-Suomi / Central and Western Finland, Finland. August

Pete Oxford / Pink flowers (Triplaris sp) at edge of water, Northern Pantanal, Mato Grosso, Brazil.

Willem Kolvoort / Water Knotweed (Persicaria amphibia) in flower, Rotterdam area, Holland. August.

Willem Kolvoort / Water Knotweed (Persicaria amphibia), central Holland. July.

Adrian Davies / Japanese knotweed (Fallopia japonica) invasive species growing on banks of River Ifon, Powys, Wales, May.

Adrian Davies / Japanese knotweed (Fallopia japonica) invasive species growing on banks of River Ifon, Powys, Wales, May.

Luiz Claudio Marigo / 'Novateiro' Tree (Triplaris brasiliana) flowering on the shore of Paraguay River at the Pantanal of Mato Grosso, Taiama Ecological Station, Mato Grosso State, Western Brazil

Dong Lei / Noble rhubarb (Rheum nobile) at alpine lake, Yarlung Zangbo Grand Canyon National Park, Nyingchi Prefecture, Qinghai Tibet Plateau, Tibet, China, June.

Jami Tarris / Palo Santo (Triplaris sp) trees reflected in water, Tagus Cove, Isabela Island, Galapagos Islands, Ecuador

Terry Whittaker / Plastic and woody debris (mostly Japanese knotweed) washed down the River Irwell into Salford Quays after a storm, Manchester, UK. January, 2023.

Ashley Cooper / Water bistort (Persicaria amphibia) in flower on Lake Windermere, Ambleside, Lake District, Cumbria, UK. June.

Ashley Cooper / Water bistort (Persicaria amphibia) and Buttercups (Ranunculus sp.) flowering in a hay meadow, Ambleside, Lake District, Cumbria, UK. May.

Ashley Cooper / Water bistort (Persicaria amphibia) in flower, Ambleside, Lake District, Cumbria, UK. May.

Ashley Cooper / Water bistort (Persicaria amphibia) and Buttercups (Ranunculus sp.) flowering in a hay meadow, Ambleside, Lake District, Cumbria, UK. May.

Ross Hoddinott / Scarce chaser dragonfly (Libellula fulva) covered in dew, roosting on common sorrel (Rumex acetosa), Lower Tamar Lakes, Cornwall, UK. May.

Doug Allan / Moorhen (Gallinula chloropus) parent feeding its chicks Water smartweed (Persicaria amphibia) in a pond, Compton Martin, Somerset, England, May.

Doug Allan / Moorhen (Gallinula chloropus) parent and chick feeding on Water smartweed (Persicaria amphibia) in a pond, Compton Martin, Somerset, England, May.

Doug Allan / 14 day old Moorhen (Gallinula chloropus) chick swimming through Water smartweed (Persicaria amphibia) on pond, Compton Martin, Somerset, England, May.

Doug Allan / Moorhen (Gallinula chloropus) parent bringing food to 14 day old chick while paddling through pond covered with Water smartweed (Persicaria amphibia), Compton Martin, Somerset, England, May.

Doug Allan / Moorhen (Gallinula chloropus) parent with three 14 day old chicks swimming through Water smartweed (Persicaria amphibia) in pond, Compton Martin, Somerset, England, May.

SCOTLAND: The Big Picture / Common bistort (Persicaria bistorta) growing on riverbank in wetland habitat, Ballinlaggan, Scotland, UK. August.

SCOTLAND: The Big Picture / Common bistort (Persicaria bistorta) growing on riverbank in wetland habitat, Ballinlaggan, Scotland, UK. August.

Nick Upton / Close up of Redshank (Persicaria maculosa) flowering, Merthyr Mawr Warren National Nature Reserve, Glamorgan, Wales, UK. July.

Nick Upton / Redshank (Persicaria maculosa) flowering by a marshy stream through coastal sand dunes, Merthyr Mawr Warren National Nature Reserve, Glamorgan, Wales, UK. July.

Nick Upton / Redshank (Persicaria maculosa) flowering by a marshy stream through coastal sand dunes, Merthyr Mawr Warren National Nature Reserve, Glamorgan, Wales, UK. July.

Ashley Cooper / Japanese knotweed (Fallopia japonica), a highly invasive, alien plant growing along the River Wye, Cleddon, Gloucestershire, UK. June.

Doug Gimesy / Aerial view of a section of Middle Reedy Lake with floating mats of Water fern (Azolla sp.) Tangled lignum (Duma florulenta) Reeds (Typha sp.) and Water primrose (Ludwigia peploides) Kerang, Victoria,...

Doug Gimesy / Aerial view of a section of Middle Reedy Lake with floating mats of Water fern (Azolla sp.) Tangled lignum (Duma florulenta) Reeds (Typha sp.) and Water primrose (Ludwigia peploides) Kerang, Victoria,...

Doug Gimesy / Aerial view of a section of Middle Reedy Lake with floating mats of Water fern (Azolla sp.) Tangled lignum (Duma florulenta) Reeds (Typha sp.) and Water primrose (Ludwigia peploides) Kerang, Victoria,...

Doug Gimesy / Aerial view of volunteers from Native Fish Australia) and Austral Research and Consulting checking bait traps by canoe for endangered Southern purple spotted gudgeon (Mogurnda adspersa). Part of capti...

Doug Gimesy / Aerial view of a section of Middle Reedy Lake with floating mats of Water fern (Azolla sp.) Tangled lignum (Duma florulenta) Reeds (Typha sp.) and Water primrose (Ludwigia peploides) Kerang, Victoria,...

Doug Gimesy / Aerial view of a section of Middle Reedy Lake with floating mats of Water fern (Azolla sp.) Tangled lignum (Duma florulenta) Reeds (Typha sp.) and Water primrose (Ludwigia peploides) Kerang, Victoria,...

Linda Pitkin / Water pepper (Persicaria hydropiper). Hampton Court, Richmond Upon Thames, England, UK. September.

Linda Pitkin / Water dock (Rumex hydrolapathum), Canada Water, Rotherhithe, Surrey, England, August.

Linda Pitkin / Redshank (Persicaria maculosa) and Water-pepper (Persicaria hydropiper) The Moors SWT, Nutfield Marsh, Merstham, Surrey, England, August.