Aquatic Invasive Weeds


Aquatic Invasive Weeds – The Problem

A whole range of aquatic invasive plants have recently entered Britain, partly due to the increase in popularity of garden ponds, indoor fish tanks and the growth of aquatic garden centres and nurseries. The Environment Agency’s list of “top ten invasive species marked for containment and removal" detail Australian Swamp Stonecrop (Crassula helmsii), Parrots Feather (Myriophyllum aquaticum), and Floating Pennywort (Hydrocotyle ranunculoides). Most aquatic plants have one common characteristic; their rapid growth chokes out native plants and overwhelms watercourses to such an extent that it can be impossible to see the water.

Aquatic Invasive Weeds – The Law

In Scotland, a variation (amendment), to Part II of Schedule 9, the Wildlife and Countryside Act 1981 was made. Australian Swamp Stonecrop, Parrots Feather, and Floating Pennywort were added to the original list of plants, making it a statutory offence to cause or allow these plants to grow in the wild. There was no amendment made for England and Wales, although adjoining land owners may take civil action utilising the general principles relating to nuisance claims, and may seek damages due to the spread of invasive weeds onto their property.

Aquatic Invasive Weeds – Information and Identification

Floating Pennywort is an herbaceous, hardy, perennial aquatic plant, usually found in watercourses rich in nutrients. The weeds float on the surface, and form dense mats. The plants have many roots that are thin and fibrous. Parrot’s Feather can grow on land and in water, and is a rhizomatous perennial. Its stems reach several metres long, and like the above, cover watercourses in thick carpets of vegetation. Similar to Japanese knotweed, its rhizomes are brittle and the plant can propagate itself by growth of the small fragments of parent plants. Australian Swamp Stonecrop can take root from a single node and stem fragment of 5mm in length, and can be identified by its pretty white flower. Severe oxygen depletion can occur below dense growths of this plant. The plant assimilates CO2 for 20 hours of the day when submerged due to crassulacean acid metabolism and grows throughout the year; there is no dormant period.

Aquatic Invasive Weeds – The Solution

Herpetosure Invasive Solutions has a range of tried and trusted cost-effective environmentally aware solutions, to fit client’s timescales, budgets, and site specific requirements, as well as meeting all regulations.