Reproduction: Typically displays little variation in growth patterns throughout the year when grown in tropical environ-ments; however, when grown in more moderate environments the plant spends most of its energy on starch production and storage in the winter and canopy growth during the summer season. Can spread through transport of plant fragments.
Submerged Large-flowered Waterweed
Large-flowered Waterweed is an Aquatic plant native to Argentina, Brazil, and Uruguay, growing in water up to 4 m deep, with trailing stems to 2 m or more long, producing roots at intervals along the stem.
Leaves are produced in whorls of four to eight, 1–4 cm long and 2–5 mm broad, with a pointed leaf tip.
The stem system of the plant will grow until it reaches the surface of the water, where it will begin to spread out, creating a thick flower canopy that blocks light from reaching plants below it.
How To Identify Large-flowered Waterweed?
Leaf: Whorled green leaf 4-8 1-4 cm long with pointed tip
Flower: white with 3 petals and yellow stamen
Roots: Appear along stems, can grow up to 4m deep
Large-flowered Waterweed - Egeria densa Flowers
Large-flowered Waterweed - Egeria densa ID Guide
Why Is Large-flowered Waterweed A Problem?
Out competes native species. Most of its impact occurs in the shallow waterways; the plant forms thick mats that obstruct boat passage, clog water intakes and aqueducts, trap sediments, crowd out native vegetation, and impede the migration of anadromous fish.
Large-flowered Waterweed - Invasive Species Information
What Is Large-flowered Waterweed - (Egeria densa)?
Habitat: Aquatic, fresh water
Distribution in Ireland: Sparse distribution but locally abundant in some places.
Status: Established
Family name: Hydrocharitaceae
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European Communities (Birds and Natural Habitats) Regulations 2011 non-native invasive plant species A-Z (Updated 2017)
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There are currently 35 invasive plant species listed in the European Communities (Birds and Natural Habitats) Regulations (annex 2, Part 1)...
Click on a species from the following list to find out more regarding non-native species subject to restrictions under Regulations 49 and 50.
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American Skunk-Cabbage - Lysichiton americanus
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Brazilian Giant-Rhubarb - Gunnera manicata
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Broad-Leaved Rush - Juncus planifolius
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Cape Pondweed - Aponogeton distachyos
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Cord-Grasses - Spartina (all species and hybrids)
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Curly Waterweed - Lagarosiphon major
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Dwarf Eel-Grass - Zostera japonica
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Fanwort - Cabomba caroliniana
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Floating Pennywort - Hydrocotyle ranunculoides
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Fringed Water-Lily - Nymphoides peltata
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Giant Hogweed - Heracleum mantegazzianum
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Giant Knotweed - Fallopia sachalinensis
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Giant-Rhubarb - Gunnera tinctoria
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Giant Salvinia - Salvinia molesta
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Himalayan Balsam - Impatiens glandulifera
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Himalayan Knotweed - Persicaria wallichii
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Hottentot-Fig - Carpobrotus edulis
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Japanese Knotweed - Fallopia japonica
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Large-flowered Waterweed - Egeria densa
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Mile-a-Minute Weed - Persicaria perfoliata
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New Zealand Pigmyweed - Crassula helmsii
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Parrots Feather - Myriophyllum aquaticum
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Red Alga - Grateloupia doryphora
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Rhododendron - Rhododendron ponticum
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Salmonberry - Rubus spectabilis
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Sea-Buckthorn - Hippophae rhamnoides
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Spanish Bluebell - Hyacinthoides hispanica
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Three-Cornered Leek - Allium triquetrum
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Wakame - Undaria pinnatifida
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Water Chestnut - Trapa natans
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Water Fern - Azolla filiculoides
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Water Lettuce - Pistia stratiotes
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Water-Primrose - Ludwigia (all species)
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Waterweeds - Elodea (all species)
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Wireweed - Sargassum muticum