Knot in my back yard

Cornwall has been an initial planting site for many introduced plants. The second recorded escape of Japanese knotweed into the wild was noted in the county in 1906. The dramatic increase in transportation of materials in the second half of the twentieth century has resulted in the spread of the plant in this area as in many others. The issue of Japanese knotweed was raised in Cornwall's Biological action plan in 1996.

A particular trigger for action was the fact that final restoration of trenching along a length of the main trunk road through the county was reinstated with material infested with Japanese knotweed. Any engineer, realising its  damaging potential and the hourly remediation costs which were involved using mobile roadworks with work vehicles, crash cushion and two back marker vehicles are enough to make him think twice about the often used comment "it's just a plant".

The strategy developed in Cornwall is to educate the population and to demonstrate the environmental and economic advantages of timely, appropriate action. A forum was established in 1997, open to all, with the members from industry, councils, agencies and individuals with the objective of strategic management of knotweed. Thus members can sign up to the forum without an immediate requirement to remove all the plant from their land, but to work, with assistance, to prioritise action according to intended future land use, risk of spread etc. The forum invites reports of sites to be recorded on a publicly available database and to promote best practice by carrying out control on all sites under the ownership or control of the council.

Dumping of unwanted plants on the verge combined with the necessarily linear nature of works in the highway corridor has resulted in considerable spread. More than 1,700 sites are recorded within the highway corridor in Cornwall. These vary from just a single stem to dense infestations which have crossed from neighbouring land. In many cases action by the council has encouraged neighbouring landholders to initiate control. This proactive approach means that where the council has treated and dealt with the plant it has a strong defence against any possible legal action for nuisance. Conversely, if a neighbour has not carried out control, action for nuisance could be considered. Signs are put on site to inform members of the public of the action being taken and to ensure those working within the area know that the plant is present and avoid disturbing it. Monitoring is continued for a period after the last above ground shoots are noted to ensure the control has been effective.

Watercourses are also frequently affected by the plant, with damage to banks and causing obstruction to channels.
The Forum has been involved in a number of projects where the whole catchment is considered due to the likelihood of the plant colonising rapidly downstream. It makes sense to start at the top.

Cornwall is often cited as a particular problem area for Japanese knotweed, but the problem is general over many areas of the country. The difference in Cornwall is recognition and recording of the issue and a determination to address the issue for the benefit of one and all.

When the Cornwall Knotweed Forum received its gold medal at Chelsea Flower Show for a display featuring the problem of Japanese knotweed, a common comment was "at last someone is doing something about that terrible plant".