These tables summarise habitat requirements and management features of characteristic waterway and wetland plants. Species are common and widespread unless otherwise noted, and most are suitable for introduction to new aquatic or wetland areas within the limits noted. A few species have been included which are relatively rare or more typical of other habitats, but have some management importance in aquatic environments.
Plants are listed alphabetically by common name in five tables, each table corresponding to a successional zone. Divisions between zones are often blurred, and species placed in one table may occur in adjacent zones. Sometimes plants are weakened or stunted or appear quite different in these conditions. For example, certain typically emergent plants may remain submerged in flowing waters, where they do not flower, and produce soft, strap-like leaves rather than stiff leaves. True aquatic species cannot survive even short-term drying, and remain under or on the surface except when they produce emergent flower spikes.
Nomenclature follows that used in the Excursion Flora of the British Isles (Clapham, A R, Tutin, T G and Warburg, E F; 1968). An asterisk before the common name indicates a non-native, introduced species, although in most cases these are naturalised. The abbreviations ‘N’, ‘S’, ‘SE’ etc refer to general regions of Britain, but distributions cannot be indicated precisely in the limited space.
IMPORTANT: Invasive, non-native plants can have massive impacts on ecosystems. Both marginal and submerged wetland plants can spread very quickly along watercourses. If you have ANY doubt about introducing a wetland plant, contact the Aquatic Plant Management Group/CEH.
NOTES, TABLES 1-5
Nutrient status: O = oligotrophic, M = mesotrophic, E = eutrophic
Management notes: I = Invasive, V = visual amenity value, X = interfere with boating or fishing, P = easily propagated by cuttings (Pc), division (Pd), seeds (Ps) or transplanting (Pt) * non-native, introduced species
TABLE 1: FREE-FLOATING TYPES
| Species | Nutrient status | Conditions | Management notes | Distribution/features |
|---|---|---|---|---|
| Algae, free- floating types | O-E | Still-slow | Blooms, blanket weed in eutrophic water | Control with barley straw. |
| Bladderwort (Ultricularia spp) | O-M | Still-slow, sheltered to 1m on peat, gravel, mud | (X) Wildfowl food | Mainly N, local elsewhere. Submerged, insectivorous. Winter turion |
| Duckweed (Lemna spp) | M-E | Still-slow. Tolerates wide range of pH and pollution | (I) May choke surface. Wildfowl food | See here |
| Frog-bit (Hydrocharis morsus-ranae) | E | Still | Invertebrate habitat, feeding area for fish | Local, not Scotland. Leaves like small water lily. Winter turion |
| Hornwort (Ceratophyllum spp) | M-E | Still-slow, incl. brackish to 1m or more | (I, V, X, Pc) Invertebrate habitat, wildfowl food | Most common SE, local elsewhere. Easily cleared. Increasing C demersum indicates declining water quality. |
| *Water fern (Azolla filiculoides) | M-E | Still-slow, esp brackish backwaters, dredged dykes | (I) May form dense mats on surface like duckweed | Local S. Not recommended for introduction |
| Water soldier (Stratiotes aloides) | M-E | Still-slow, shallow, unpolluted, alkaline | May grow densely. Sinks in winter or if put in deep water | Local E, decreasing. |
TABLE 2: SUBMERGED ROOTED PLANTS
| Species | Nutrient status | Conditions | Management notes | Distribution/features |
|---|---|---|---|---|
| Awlwort (Subularia aquatica) | O | Still, acid, to 1.5m on exposed shores | Difficult to establish | Local in mountains of W, N |
| * Canadian pondweed (Elodea canadensis) | M-E | Still-medium, 0.3-3m | (I) Often chokes water. Invertebrate habitat | Survives winter as shoots (tight-wrapped leaves) |
| Horned pondweed (Zannichellia palustris) | E | Still-med, incl brackish, to 2m, clay streams | (I,X) Invertebrate habitat, pochard food | Lowlands. Tolerates phosphate pollution |
| Lesser marshwort (Apium inundatum) | O-M | Still-slow, shallow, sheltered, on peat | — | Tolerates fluctuating water levels |
| Mare’s tail (Hippuris vulgaris) | M-E | Still-med, often alk, shallow or emergent | (X) Wildfowl food (seeds) | Tolerates fluctuating water levels |
| Moss (Fontinalis antipyretica) | O-E | Still, deeper water | Hard to establish | Easy to manage if present |
| Pondweed, blunt- leaved (Potamogeton obtusifolius) | O-M | Still-slow, neutral- acid to 3m, stream mouths | (I) Wildfowl food | Mainly SE, scattered elsewhere. Rampant in eutrophic water |
| Pondweed, curled (P crispus) | M-E | Still-fast, clear, to 1m on clayey mud | (I,X) Fish and insect shelter, wildfowl food | Difficult to control |
| Pondweed, flat- stalked (P friesii) | E | Still-slow, to 2m | (X) Wildfowl food | Locally frequent in lowlands |
| Pondweed, fennel (P pectinatus) | E | Still-fast, incl brackish, 0.6-2.5m | (I,X) Invertebrate habitat, wildfowl food | Wide range of conditions incl polluted, turbid. Pondweed sp most likely to cause problems to flow and navigation |
| Pondweed, hair- like (P trichoides) | M-E | Still-slow, shallow, sheltered sites | (I,X) Invertebrate habitat, wildfowl food | Scattered, very local S, E, C |
| Pondweed, long- stalked (P praelongus) | M-E | Still-slow, clear, 1-6m on silt, fen peat, limestone | Wildfowl food | Locally frequent, NE, C, E, rare elsewhere |
| Pondweed, perfoliate (P perfoliatus) | O-E | Still-med, clear, 1-4m on gravel, clay | Wildfowl food | Invasive when no competition |
| Pondweed, red (P alpinus) | O-M | Still-med, acid, clear, shallow on mud or rock | (X) Wildfowl food | Locally frequent N, C, SE. Tolerates spates |
| Pondweed, shining (P lucens) | E | Still-slow, alk, clear, to 4m on limestone, clay | (X) Wildfowl food | Frequent in lowlands of SE, C, rare elsewhere |
| Pondweed, slender-leaved (P filiformis) | E | Still-slow, esp brackish, 100-700mm on sand | Wildfowl food | Scattered N, Anglesey, mostly near coast |
| Pondweed, small (P berchtoldii) | M-E | Still-slow, acid-alk, to 1m, sheltered sites | (I,X) Invertebrate habitat, wildfowl food | — |
| Pondweed, small (P pusillus) | M-E | Still-slow, alk, incl slightly brackish, to 3.6m on clayey mud | Wildfowl food | Locally frequent S, C, E, C Scot, scattered elsewhere |
| Pondweed, various-leaved (P gramineus) | O-E | Still-slow, acid, to 3m in clear water | Wildfowl food | Locally frequent, mainly N, E. Tolerates some pollution |
| Quillwort (Isoetes spp) | O-M | Still, acid, to 3m on stony or boulder clay | Difficult to establish | Local in W and N highlands |
| Shoreweed (Littorella uniflora) | O-E | Still, esp acid, to 4m | Wildfowl food | Pioneer, stabilises loose sand, gravel. Stands exposure |
| Starwort (Callitriche spp) | O-E | Still-fast, acid-alk, to 1m or more depending on spp | (X) Wildfowl food | — |
| Stonewort (algae, mainly Chara and Nitella spp) | O-E | Still, clear, acid-alk or brackish, to 3m on silt, sand, mud | (Pt) Wildfowl food, cover. Grows rapidly | Resembles higher plants. Nitella important in nutrient-poor upland lakes |
| Tassel pondweed (Ruppia maritima) | M-E | Brackish on sandy or fertile soil | Dabbling duck food (seeds) esp wigeon | Local, coastal pools and ditches |
| Water crowfoot (Ranunculus spp) | O-E | Still-fast, depending on spp, incl brackish | (I,V,X) Invertebrate habitat, wildfowl food (seeds) | Often dominant in swift water |
| Water lobelia (Lobelia dortmanna) | O | Acid to 1.2m on peat or gravel | (V) | W, N. Showy emergent flower spikes |
| Water milfoil (Myriophyllum) | O-E | Still-fast, acid-alk, to 2m depending on spp | (I) Invertebrate habitat, wildfowl food. Casts little shadow | Myriophyllum spicatum can become rampant in still, eutrophic water |
| Water violet (Hottonia palustris) | E | Still-slow, shallow esp ditches | (V,X) | Local E, rare elsewhere, not Scot |
| Waterwort (Elatine spp) | M | Still, to 600mm, on exposed shores | Needs varying water levels | Scattered in S, W, N |
TABLE 3: FLOATING-LEAVED ROOTED PLANTS
| Species | Nutrient status | Conditions | Management notes | Distribution/features |
|---|---|---|---|---|
| Bur-weed, floating (Sparganium angustifolium) | O | Still, clear, 0.6-2m on fine organic soil | (X) | Local in mountainous areas, rare elsewhere. |
| Bur-weed, unbranched (Sparganium emersum) | O-E | Still-med, to 1m esp clay streams, basic soil | (I,X,Pd) Wildfowl food and cover | Frequent S, E, C, local elsewhere. Cannot stand waves |
| Pondweed, broad- leaved (Potamogeton natans) | O-E | Still-med, usually clear, 0.3-3m on soft, rich soil | (X) Attracts insects. Food for mallard, teal (seeds), swans (roots) | Tolerates spates and more acid conditions than many Potamogeton spp |
| Fringed water lily (Nymphoides peltata) | E | Still-slow, incl turbid, 0.6-1.5m esp fen drains, new water bodies | (V,X) Attractive but can be invasive | Becoming a problem in some static waters in S and E. |
| Least water lily (Nuphar lutea) | M-E | Still, 0.6-2.5m | (X) | Local in highland Scot, rare in Shropshire |
| White water lily (Nymphaea alba) | M-E | Still-slow, incl turbic, to 3m | (I,V,X) Suitable for stream mouths | — |
| Yellow water lily (Nuphar lutea) | M-E | Still-med to 2m or more nitrogenous | (I,V,X) Suitable for stream mouths | — |
TABLE 4: EMERGENT PLANTS
| Species | Height | Nutrient status | Conditions | Management notes | Distribution/features |
|---|---|---|---|---|---|
| Amphibious bistort (Polygonum amphibium) | — | M-E | Still-slow, to 600mm or more, exposed shores, usually non-calcareous | (V,Pd) Insect habitat, duckling cover, wildfowl food (seeds) | Tolerates spates, fluctuating water levels and dessication. Showy flowers. |
| Arrowhead (Sagittaria sagittifolia) | 300mm | M-E | Still-med, to 150mm on sand, silt, clay | (V) Duckling cover, wildfowl food (tuber). Regrows when cut | S, E, C. Submerged, strap-like leaves in flow. Dies down after first frost |
| Bur-reed (Sparganium erectum) | — | M-E | Still-med, to 1m esp on basic soil, clay | (I, Pd) Wildfowl food and cover | The most widely distributed stream plant. Cannot stand waves |
| Common bulrush or club-rush (Schoenoplectus lacustris syn Scirpus lacustris) | 2-2.5m | O-E | Still-med, 1-2m (less in flow) on 30-60% organic- content soil | (I,V) Wildfowl food and cover | Mainly lowlands of S, E, C esp outer fringe of Phragmites swamp. Withstands wind and waves. |
| Common or Norfolk reed (Phragmites communis) | 2.4m | O-E | Still-slow, to 2m on 30-60% organic- content soil, sheltered sites | (I,V,Pdc) Reed warbler, bunting habitat, wildfowl food | See here. Dominates inner margins of reedswamp. Stands drying, not waves. |
| Floating sweet- grass (Glyceria fluitans) | 0.3-1.2m | M | Still-med, shallow margins. Extends by floating, trapping ooze | (Psd) Wigeon, swan food (leaves), other wildfowl food (seeds) | Tolerates fluctuating water levels, scour |
| Flowering rush (Butomus umbellatus) | 1m | M-E | Still-slow, shallow margins, esp on clay | (V,Pd) | Mainly lowlands of SE, C. Showy flowers |
| Glaucous club- rush (Scirpus tabernaemontani) | 1m | M-E | Still incl brackish, peaty to 500mm | — | Locally frequent S, E, W coasts, scattered throughout |
| Lesser or narrow-leaved reedmace (Typha angustifolia) | 2m | M-E | Still, to 0.6-2m, esp floating mat over deeper water | (I,V) Wildfowl cover, invertebrate habitat | Often in mono- dominant stands. Tolerates summer cutting but not pollution |
| Lesser spearwort (Ranunculus flammula) | 300mm | O-E | Still-swift, varying soils esp acid organic | (V) Invertebrate habitat, bird food (seeds) | Tolerates shade |
| Lesser water plantain (Baldella ranunculoides) | 300mm | M-E | Still-slow, neutral-alk, shallows on mineral soil | (V) Easy to establish, good bottom cover to 500mm | Local, widely scattered |
| Reed canary grass (Phalaris arundinacea) | 1.2m | M-E | Still-fast to 1m | (V) Mallard food (seeds), cover. Locally invasive | Tolerates fluctuating water levels, strengthens banks |
| Reedmace or bulrush (Typha latifolia) | 2m | M-E | Still, to 600mm or so on med (35%) organic content silt, or floating mat | (I,V) Duckling cover, invertebrate habitat | Often in mono- dominant stands. Tolerates pollution, silting |
| *Sweet flag (Acorus calamus) | 1.2m | M-E | Still-med, esp alk, to 500mm on silt | (Pd) Sterile in west Europe | Mainly S, E, C. Medieval introduction for mats. |
| Water horsetail (Equisetum fluviatile) | — | O-E | Still-slow, medium alk, to 1m on sand, peat | (I) Fish habitat, mallard food. Toxic to stock, palatable when cut | Often mono- dominant in open water less than 150mm deep. |
| Water plantain (Alisma plantago- aquatica) | — | M-E | Still-med to 750mm on silt | (I,V) | Narrow-leaved water plantain (A. lanceolatum) similar, SE |
| Watercress (Rorippa nasturtium- aquaticum syn Nasturtium officinale) | 600mm | M | Still-fast, esp shallow, clear, unpolluted, sunny, on limestone gravel | Invertebrate habitat, wildfowl food (shoots) | Often cultivated |
TABLE 5: MARGINAL PLANTS
| Species | Height | Nutrient status | Condition | Management notes | Distribution/features |
|---|---|---|---|---|---|
| Bogbean (Menyanthes trifoliata) | — | O | Still-slow, acid, shallow or floating mat on deep peat, anaerobic mud | (V) | — |
| Bogmoss (Sphagnum spp) | — | O | Acid peat in pools or on hummocks, depending on spp | Supports specialised bog plant community | Cannot stand trampling, burning |
| Common spikerush (Elecharis palustris) | 300mm | M | Still-slow, to 300mm, on varied soils | Wildfowl food (seeds) and cover | Often mono- dominant on exposed shores |
| Cottongrass (Eriophorum spp) | 600mm | O | Acid bog, peat moor | — | — |
| Creeping buttercup (Ranunculus repens) | 450mm | — | Slow current in water, wet meadows | (V) Dabbling duck food (seeds, leaves) | Typical of grazed and disturbed marshes |
| Great water dock (Rumex hydrolapathum) | 1.5m | E | Still-slow, to 500mm esp on clay, fen peat | (Psd) Insect food, wildfowl food (seeds) | Mainly SE, C. Esp in canals |
| Kingcup or marsh marigold (Caltha palustris) | 300mm | O-E | Still-slow or damp mineral soils | (V) Flowers early, imp to pollinating insects | Typical of marshes, wet meadows. Showy flowers. Toxic to |
| Marsh cinquefoil (Potentilla palustris) | 450mm | O-M | Still, sheltered margins or floating mats | (V) Cover | Common except S, E. Often with bogbean |
| Marsh yellow- cress (Rorippa islandica syn Nasturtium palustre) | 300mm | — | Slow, esp where water stands only in winter | Swan and wigeon food (roots) | — |
| Narrow-leaved water-parsnip (Berula erecta) | 450mm | M | Still-fast, esp alk, shallow margins on limestone, fen peat | — | Frequent SE, C, elsewhere rare. Tolerates shade |
| Orache (Atriplex spp) | 1m | — | Waste or disturbed ground or sand, gravel shores | Wildfowl food (seeds) | Esp coasts. Quickly colonises new ground |
| Pennywort or marsh pennywort (Hydrocotle vulgaris) | — | O-E | Still-slow, acid- alk, to 800mm on peat | — | — |
| Purple moor- grass (Molinia caerulea) | 600mm | O | Acid peat | — | — |
| Redleg or redshank (Polygonum persicaria) | 600mm | — | Waste places, cultivated soils, beside ponds | Wildfowl food (seeds) | Quickly colonises new ground |
| Rush, bulbous (Juncus bulbosus) | 600mm | O | Still-med, acid, clay or peat on hard rock or acid sandstone | (Ps) | Aquatic form (fluitans) in water to |
| Rush, hard (J inflexus) | 600mm | O-E | Shallows, neutral-alk soil | (Ps) Wildfowl food (seeds), redshank cover | Protects shore from erosion. Toxic to stock |
| Rush, soft (J effusus) | 700mm | O-E | Shallows, acid soils, clay | (Ps) Wildfowl food, cover. | Protects shore from erosion. Once used for rush lamps |
| Rush, jointed (J articulatus) | 450mm | O-E | Shallows, acid soil esp mown and grazed meadows | (Ps) Wildfowl food (seeds) | Juncus marshes often rich in orchids |
| Saw or great fen sedge (Cladium mariscus) | 1.5m | M | Still, alk, shallows on fen peat | (I) Wildfowl cover | Mainly E. |
| Sea clubrush (Scirpus maritimus) | 600mm | M-E | Still, esp brackish, shallows | Wildfowl food (seeds), nest cover | Often mono- dominant. Tolerates summer drought |
| Sedge, bottle (Carex rostrata) | 450mm | O-M | Still, acid-alk, to 600mm on peat | (I,Pd) Wildfowl food, cover | Mainly uplands of N, W, S, where constant high water table |
| Sedge, common (Carex nigra) | 300mm | O-E | Usually acid | (Pd) Wildfowl food (seeds) | — |
| Sedge, greater pond (Carex riparia) | 1.2m | E | Still-slow, to 600mm on mineral- organic soil | (Pd) Bird food (seed, leaf), breeding cover | Mainly lowlands S, E, C. Stands summer cutting |
| Sedge, greater tussock sedge or panicled (Carex paniculata) | 1.2m | E | Still-slow, alk, shallows, often above mean water level, on fen peat | (V,Pd) Wildfowl cover | Tolerates some shade. Protects shoreline from erosion |
| Sedge, hammer or hairy (Carex hirta) | 600mm | — | In damp grass, near ponds | (Pd) Wildfowl food (seeds) | — |
| Sedge, lesser pond (Carex acutiformis) | 700mm | E | Still-very slow, to 600mm on silt, clay | (Pd) Wildfowl food | Mainly lowlands S, E, C. Often co-dominant with C riparia. |
| Small-reed (Calamagrostis spp) | 300mm--1.5m | — | — | — | Harmed by summer flooding |
| Tufted hair- grass (Deschampsia caespitosa) | 1m | — | Acid, clayey soils | Breeding cover for birds | — |
| Water forget- me-not (Myosotis scorpioides) | — | O-E | Still-fast, margins to 500mm, varied soils | (V) | Tolerates shade, fluctuating water levels |
| Water mint (Mentha aquatica) | 300mm | M-E | Still-fast, esp alk, shallows esp on limestone | — | Tolerates fluctuating water levels |
| Water pepper (Polygonum hydropiper) | 600mm | — | Marshy fields, trampled margins and shallows | Mallard food (seeds) | Toxic to stock |
| Yellow flag (Iris pseudacorus) | 1m | O-E | Still-slow, shallows, on silt | (V) | May indicate summer drying. Remains toxic when cut. |
