Common names: Parrots feather, M. brasiliense, M. propernaciodes, M. propium
Habitat: Freshwater aquatic systems. Adapted to high nutrient environments. It tends to colonize slowly moving or still water rather than in areas with higher flow rates
Description: This species is similar to a native species of Myriophyllum, otherwise known as water milfoil. It is an aquatic invasive plant but has been recorded to survive in dried out ponds as well as on dry banks in Britain. So far, only female plants have been recorded in Britain and Ireland. As a result this species reproduces solely by fragmentation. The species gets its name from the feather like blue-green leaves that arranged in whorls of 4-6 around the central stem. Parrots feather has both submerged and emergent leaves that grow above the surface of the water. The submersed leaves are 1.5 to 3.5 centimeters long and have 20 to 30 divisions per leaf. The emergent leaves are 2 to 5 centimetres long and have 6 to 18 divisions per leaf. The bright green emergent leaves are stiffer and a darker green than the submersed leaves. The emergent stems and leaves are the most distinctive trait of M. aquaticum, as they can grow up to a foot above the water surface and look almost like small fir trees. Garden centres are also known to sell similar species that are also recognised invasive species. These may be labelled as M. brasiliense, or M. propernaciodes, or M. propium. Forms small (2mm) inconspicuous white flowers May-August.
Origin and Distribution: The species is native to South America where both male and female forms are known.
Impacts: This species is capable of out competing native macrophytes, reducing species diversity. There is also a possibility that this species will clog waterways leading to problems for drainage and access.
How did it get here? The species was brought to Ireland as a garden pond plant.
Where is it found in Ireland? In Northern Ireland Parrots Feather has only been recorded at one site in the Ards Peninsula, County Down. In the Republic of Ireland Myriophyllum aquaticum has been recorded at a number of sites. The number of garden ponds with this species is unknown.
- Promote native species and biodiversity - use alternative, native plants
- Know what you are buying/growing and source native Irish seed and plants
- Do not swap plants and cuttings
- Clean plants before adding to ponds (dispose of water away from water courses)
- Follow control advice and watch out for hitchhikers - inspect new imported purchases for invasive pest and pathogens
- Clean equipment before moving between waterbodies
- Never collect plants from the wild
- Safe disposal of plant material and growing media