Overstrand Sea Wall Japanese Knotweed

Date published: 29th September 2025

In March, North Norfolk District Council closed the central section of the sea wall in Overstrand following a cliff slip, which was later found to contain Japanese Knotweed.

Over the next eight weeks, work will be undertaken to remove the slip material, treat the knotweed and stabilise the slope. 

The material on the central section of the sea wall

Timings of these works will be as follows: 

• Week commencing Monday Sept 29 - Non-contaminated material removed from the sea wall and disbursed locally. 

• Week commencing Monday October 6 - Weedkiller will be applied covering a three-metre stretch at the base and top of the cliff (to be repeated two to three times over the next few years) 

• Week commencing Monday Oct 27 - A licensed contractor will remove cliff material containing Japanese knotweed from the sea wall and dispose of it in a controlled manner 

• Stabilisation work at the base of the slope will then be undertaken to retain slip material and help prevent further contaminated material from slipping onto the sea wall  

 

Japanese Knotweed at Overstrand, pictured from above

Exact timings of these works will heavily depend upon weather and tidal conditions.

During the weedkiller application the whole sea wall area will be closed for public access as shown on the plan, with beach access still being available to the east and the west. 

During the cliff material removal and stabilisation works, the closure area will be widened to include the beach access slope from Clifton Way. During these works, access to the beach will only be possible via the west end only. 

Programme: 

Stage 1: Removal of non-knotweed slip - October 2025. (Yellow lines)

Stage 2: Removal of knotweed slip - October 2025 (Red lines)

Stage 3: Spraying of knotweed (full closure) -  Oct/Nov 2025 (Yellow & Red lines)

Stage 4: Major scheme (full closure) - Winter 2025 & Spring 2026 (Yellow & Red lines)

There is a legal requirement for landowners to prevent Japanese knotweed from spreading, and removal and disposal must be undertaken by a suitably qualified contractor. 

FAQs 

Why is the slip material being removed in different ways? 

The Council has a legal obligation to dispose of the Japanese knotweed in a controlled manner and is using a licenced contractor. Japanese knotweed is an invasive non-native species, and we have a duty to stop it spreading. 

How much will the knotweed removal cost and how will it be funded? 

The Council has established a budget for this but the actual cost will not be known until the full extent is established. 

How will residents and businesses be affected by the works? 

The removal of the slip material will be taken from the east of the promenade and up the slope to Clifton Way. The residents on Clifton Way may experience disruption from lorries accessing the road to get to cliff slip material. Parts of the promenade will be closed when the different works are underway. 

What times will the work be taking place? 

Work may be weather and tide dependent but will be undertaken during daylight hours.  

How will the knotweed be removed? 

The knotweed in situ will be sprayed with weedkiller but the cliff slip material containing Japanese knotweed, will be taken away by a licenced contractor. The material will be loaded onto lorries straight from the promenade and removed from site via the access road to Clifton Way. 

Is the treatment method for knotweed safe, are there alternatives? 

The Council has looked at alternative methods but due to characteristics of this location, with unstable cliffs, the knotweed needs to be sprayed from the top and bottom of the slope. The Council is looking into the option of using drones to spray the central area of the cliff containing Japanese knotweed. 

How long will the knotweed treatment process take? 

The spraying process of the top and bottom 3m will be brief but will need to be repeated twice a year for several years. The duration of the treatment of the central section is not yet known. To completely remove the knotweed from this location and establish native vegetation will take many years. 

Is my property at risk of knotweed contamination? 

The specific measures taken to remove and eradicate the knotweed in this location are designed to prevent it from spreading.