PROJECT EXAMPLE: Bamboo and Knotweed Removal to Facilitate Summerhouse Demolition and New Construction
On this site, a derelict summerhouse was to be redeveloped by our client. Bamboo and Japanese knotweed were both prominent invasive species and required removal at the same time. Continue reading to see how we cleared this riverside site making it suitable for it’s planned development.
SITE OVERVIEW
The site was in a large garden located along the bank of the River Thames and featured:
- Gated access from the main road, with a concrete entry and small parking area.
- A main plot of grassland, interspersed with planting beds and semi-mature trees.
- Sloping ground leading to the river, with concrete steps and a small jetty.
INVASIVE PLANTS SURVEY FINDINGS
Bamboo:
A dense stand of running bamboo measuring approximately 152.88 sq. metres extended from the riverbank up towards the lawn, reaching the boundary fence and the site of an old summerhouse. There was notable rhizome spread, with runners going up the lawn.
Japanese Knotweed:
Onsite there was a mature stand of 22.05 sq. metres, partially suppressed by bamboo, which extended right down to the jetty and river.
Offsite there was also around 9 sq. metres which appeared to have spread from onsite area. Access to this stand was hampered by the dense bamboo.
REMEDIAL WORKS PLAN – Bamboo and Japanese knotweed removal
To facilitate the planned construction works on the old summerhouse site and prevent future regrowth, targeted removal and long-term control of both the Bamboo and the Japanese knotweed were required.
BAMBOO CANE CUTTING AND EXCAVATION
Approach:
- Focused on physical extraction of bamboo runners and rhizomes, particularly those invading the lawn.
- Culms (aerial stems) were cut and removed.
- Excavation of the underlying rootzone and rhizome network to a maximum depth of 200mm
- Systematic sifting of surrounding soil to extract all running rhizomes.
Post-Extraction Measures:
- All plant material stockpiled and removed from site by grab lorry.
- Excavated area backfilled with certified topsoil.
- Installation of a vertical root barrier along the bamboo boundary to prevent future spread.
JAPANESE KNOTWEED MANAGEMENT
Onsite and Offsite Areas:
- Bamboo clearance enabled access to previously obstructed Japanese knotweed stands.
- Initiation of a 5-year herbicide treatment and monitoring programme for both onsite and offsite knotweed areas, as well as any remaining bamboo.
- The programme includes annual assessments and retreatment as necessary to ensure effective long-term control.
OUTCOMES
- Immediate improvement in site condition, enabling safe and compliant redevelopment of the summerhouse site.
- Long-term management plan in place to monitor and suppress regrowth of both bamboo and Japanese knotweed.
- Installation of root barriers and removal of invasive species supports sustainable land use and protects the Thames River ecosystem.
- This approach ensures both immediate site readiness for construction and responsible, ongoing management of invasive plants.
If you have a Bamboo or Japanese knotweed infestation on your site which you need to be cleared, please contact the team for a site survey and/or treatment options.