Staff, volunteers and contractors across the Scottish Invasive Species Initiative (SISI) area have been working relentlessly to tackle the annual regrowth of Giant hogweed plants. Giant hogweed is one of the most hazardous invasive non-native species in the UK as it poses a direct risk to human health.  It has a phytotoxic sap which can cause skin burns on contact. Growing in dense stands, it prevents anything else from growing and thus reduces native species diversity. 

Using herbicide is the only successful way to treat the plant, and the most effective method of application is by spraying in the early spring when the plants are small and not yet flowering. The herbicide (Glyphosate) is applied to the leaves, which then turn yellow and die within a few days.

If left untreated the plants grow to heights of up to 3m and produce large flower heads up to 80cm in diameter.  Each plant produces about 20,000 seeds which lie dormant in the soil and then germinate in the spring into new plants.

Through training volunteers in pesticide application and providing equipment, such as backpack sprayers, to local groups the SISI project aims to form a network of local people, working in partnership with the local Fishery Trusts who can continue the control work for a number of years to come.