Originating from a single plant introduced approximately 100 years ago and although it does not produce fertile seeds, has managed to spread across much of the UK.  The reason for this is its ability to grow from a small fragment of its root, or rhizome.

It is a fast growing plant which out-competes most native species by growing quickly and shading out the ground below.  It forms large impenetrable stands and is so strong that it can grow up through tarmac.  It is a particular problem if it grows near buildings as it can undermine the foundations.

Removal should be carried out carefully ensuring the entire rhizome is removed and destroyed, or by the spraying and injecting the plant with herbicides.

Himalayan Balsam was introduced as a pretty garden plant.  It is fast growing plant which can take over an area and out shade native plants.  In some areas it is favoured by Bumblebees which can mean the bees do not pollinate native or food plants.

It dies backs in the winter and along a river bank can subsequently cause bank erosion as there are no roots to keep to soil together.  The seed heads ‘pop’ when ripe and can send the seeds over 3 metres away.

Removal is relatively easy as the plants have a shallow root system and can be pulled from the ground.  The roots should be then kept off the ground until the plant is dead.

This plant looks very similar to our native hogweed but can grow up to 3 times taller.  It was introduced from central Asia as an interesting garden plant but the 20,000 seeds produced by each flower head, has meant it has now ‘escaped’.  It forms big stands, out-competing other plants.

Removal of this plant can be difficult as the sap is toxic and can cause a strong reaction.  It burns the skin and forms large blisters.  The reaction can last longer than the blisters as the sap is photosensitive so a stinging sensation can be felt years afterwards.

Spraying Giant Hogweed with herbicides is the most effective removal method however those undertaking the work need to cover all exposed skin to prevent burns.

Native to North America, these crayfish were introduced for food in the late 1970s and 1980s but spread quickly across much of the UK.  Their recorded distribution in Scotland is limited but they have been found in the Initiative area.  They spread up and downstream and may cross land to colonise adjacent water bodies.  Human transfer, although illegal, still continues.

Negative impacts include the almost complete loss of the native crayfish through the spread of disease and direct competition.  They also undermine riverbanks through burrowing and can predate on native fish eggs and aquatic invertebrates.