Giant Hogweed

Invasive Non-Native Species (INNS)

WINNS Project

The Wear Rivers Trust is currently working to map invasive species throughout the Wear catchment. As part of our Wear Invasive non-Native Species (WINNS) Management Plan we are;

    • Gathering INNS records from the public

    • Co-ordinating volunteer walkover surveys

    • Producing INNS coverage maps 

    • Training people to identify and control INNS

    • Strategically tackling INNS in 2019 and 2020

Learn More

For more information on the various INNS please follow the link below to the  GB Non-Native Species Secretariat.

WINNS: Mapping

Building a baseline

The first stage of WINNS is, logically, mapping the current distribution of the most important INNS in the Wear catchment. Developing this accurate baseline map is vitally important in informing the Wear INNS Strategic Management plan. To create this baseline map we are;

  • Working with partners to collate all existing data available
  • Recruiting a network of volunteers to survey for INNS along watercourses
  • Training this volunteer network to collect reliable and accurate data on INNS 
  • Collating existing and volunteer data to produce an accurate map of INNS coverage in 2019

Known coverage (2019) of Himalayan Balsam (purple), Japanese Knotweed (yellow) and Giant Hogweed (gr

Known coverage (2019) of Himalayan Balsam (purple), Japanese Knotweed (yellow) and Giant Hogweed (gr


Additional Information

We are currently producing a strategy for tackling INNS across the whole Wear catchment. We will capture the current distribution and propose future activity in a WINNS management plan. We're linking with other organisations working towards the same goal, sharing knowledge and resources to be more effective. There are several other invasive species which pose a threat to UK watercourses and we will use a risk based approach to prioritise our work in future.


Winns: Management

Efficient and effective management

Where appropriate we are using volunteer effort to control INNS  in the Wear.  We seek all permissions and liaise with stakeholders to manage INNS where we can achieve the maximum benefit. The management of INNS is important because of the negative impact they can have upon the environment. INNS often form mono cultures and out compete native species which have evolved to suit the Wear catchment. 


Japanese Knotweed

Japanese knotweed (Fallopia japonica) is a perennial weed that spreads rapidly. In winter the plant dies back to ground level but by early summer the bamboo-like stems emerge from rhizomes deep underground to shoot to over 2.1m (7ft), suppressing all other plant growth. Eradication requires determination as it is very hard to remove by hand or eradicate with chemicals. Knotweed can cause damage to built structures as it can grow through masonry and even concrete. It can remain dormant for several years and can vegetate from rhizomes. Fortunately it's seeds are not viable in the UK.

Himalayan Balsam

Himalayan balsam (Impatiens glandulifera) is a relative of the busy Lizzie, but reaches well over head height, and is a major invasive weed, especially on riverbanks and waste land, but can also invade gardens. It grows rapidly and spreads quickly, smothering other vegetation as it goes. It spreads by seed dispersal, which are spread several metres by a catapulting action from the ripe seed pods. In winter it dies back, leaving river banks bare and more susceptible to erosion.

Giant Hogweed

Giant hogweed (Heracleum mantegazzianum) is widespread in lowland GB, and is invasive along lowland rivers and on waste land.   This umbellifer (member of the cow-parsley family) has flowering stems typically 2-3 m high bearing umbels of flowers up to 80 cm in diameter. The basal leaves are often 1 m or more in size. It is similar in appearance to the smaller native Hogweed (Heracleum sphondylium). Giant hogweed contains sap which, upon contact with bare skin can cause severe burns when exposed to the sunlight. 


Files coming soon.