Invasive Species


The INNS project began in April 2010 and aims to take a catchment approach to tackling invasive species. The main objective is to reduce the spread of Himalayan balsam and Japanese knotweed along the river bank improving the diversity of native species and improving access. Control work is carried out in a top down approach, starting at furthest upstream colony and working down river. This reduces the chance of any areas controlled downstream being re-colonised by infestations further upstream..

Himalayan balsam flower and seed pods


Controlling Himalayan balsam has been carried out in partnership with the Criminal Justice Service who have supplied community service work groups to cut areas of balsam along the river bank. The work has focused on the area between Three Waters Meet and Woodfoot Bridge and large areas have been cut and hand pulled. Himalayan balsam is an annual plant and the aim of the control work is to prevent seeding resulting in the depletion of the seed bank. Research has shown that this can take between 12 - 18 months.


  • Stems are hollow, jointed and brittle. Plants can grow up to 3 metres tall.  Leaves are spear shaped with serrated edges and grow in whorls of three.
  • Flowers are slipper shaped on long stalks and vary from purplish pink to pale pink.
  • The plant flowers between June and October.
  • Seed pods are produced between July and October and explode when touched

Japanese knotweed stand


Work to control Japanese knotweed started in July 2010 on Birnock Water in Moffat. Japanese knotweed is a perennial plant which grows from an extensive underground rhizome system. Although Japanese knotweed in the UK does not produce seeds it is highly regenerative and can grow from a tiny fragment of stem. Treatment has largely been carried out using a stem injection system delivering a shot of herbicide directly into the plants water reservoir. Where stem injection is not an option the plant will be treated using a knapsack sprayer. So far, approximately 1500 M2 of Japanese knotweed have been treated with last year's treatment showing encouraging signs of success.

Japanese knotweed flowers


  • Stems are green with red or purple specks and can grow up to 2-3 metres tall in dense cane like clumps.
  • Shield or heart shaped green leaves..
  • Creamy white clusters of flowers appear between August and September.

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