Knotweed Services (UK) Ltd were contacted to conduct a survey at a residential home in Great Missenden. The lady who owns the property now lives in a residential home but is in the process of selling her home. The daughter in law instructed us to carry out the survey as soon as possible due to the Japanese Knotweed on her property holding up the sale process.
The site survey concluded that three stands of Japanese Knotweed (Fallopian japonica) was present at the clients property.
Each stand was summarised below:
- JKW1 – This stand was mature and showed signs of linear encroachment along the hedgerow. The hedgerow formed a boundary feature between the clients property and the neighbouring property. I informed that the rhizome of this stand will likely extend under both properties driveways. See figures 1 – 4.
- JKW2 – A mature stand which had established with a compost heap in the corner of the garden. Access was extremely limited to this area due to dense impenetrable twigs and branches. The stand predominantly covers the clients property but also had a small amount of growth in the neighbouring garden. See figures 5 – 8.
- JKW3 – Bonsai growth less than 1m from the properties garage. The bonsai growth indicated the stand is severely stressed and had likely
been treated previously. See figures 9 – 11.
Discussions with the client and the neighbour suggested that the neighbour had been treating the knotweed on his property for several years using the ‘cut and fill’ technique. I advised that both parties abstain from any treatments. This would allow the full scale of the knotweed to be revealed. Additionally, the stands will grow and produce more leaves, creating a higher surface area to which herbicide can be applied during the optimum treatment period.
The information obtained during this site survey did not provide sufficient evidence to determine the origin of the knotweed at either properties. Any suggestions of blame would be exceptionally hard to prove. At the time of the survey, both properties were affected by knotweed and so I advised both parties (no.31 7 & no.33) to implement a joint management plan.
Given the property had outlined planning permission, I gave recommendations for two possible scenarios:
Remaining in its current state – a 5 year management plan including 3 years of herbicide treatment and 2 years of monitoring (details given in next page).
Development scenario – It is hard to comment on how any proposed development may impact the knotweed without seeing detailed drawings. If the development is expected to involve works within 7m of any knotweed than an excavation approach to treatment will be required. This is generally more costly than the first option but control could be achieved in a more quicker timeframe.
The mapping stage of our plans is crucial to identify the location of the infestation. This not only helps to indicate the proximity to boundaries/habitable space & outbuildings and the associated RICS classification, but also identifying the possible migration (7m buffer zone).
We look forward to seeing the progress with this plan and beginning 1st treatment this year between July/August time.