Understanding Japanese Knotweed
Japanese Knotweed is an incredibly invasive plant that can really wreak havoc on buildings, infrastructure, and the environment. This plant can reach heights of up to 3 metres each year, which makes it quite difficult to manage. Japanese Knotweed tends to grow in places with damp soil and can adapt well to different surroundings.
A Japanese knotweed membrane is a specific type of root barrier that helps stop the invasive spread of Japanese Knotweed, keeping its rhizomes from creeping into neighbouring properties.
Japanese knotweed rhizomes can cause significant issues in construction and landscaping, making it essential to use specialised membranes and root barriers to keep them from spreading.
What is a Japanese Knotweed Root Barrier?
A knotweed barrier is a heavy duty, puncture resistant membrane or geotextile fabric that contains the plant’s extensive root (rhizome) system, often referred to as a geocomposite root barrier system. This system includes a copper foil layer that serves as a signal layer, effectively directing plant growth away from the barrier.
When installed correctly this barrier stops the spread of knotweed by creating a physical barrier that the roots can’t get through. To be effective barriers must be buried deep enough to contain the rhizomes (2-3 metres) and securely fastened along edges. These membranes are often used in conjunction with other treatments like herbicide application.
Understanding Knotweed Root Barriers
Japanese Knotweed root barriers are key to stopping the spread of this pernicious plant that can damage properties and ecosystems. They physically block the roots from spreading to other areas.
The available barrier membranes offer the following characteristics:
High puncture, tensile and tear strengths while remaining lightweight and flexible
Indefinite service life once buried – Minimum 50 years
CE Certified, Root and Light penetration tested
Over 15 years field performance history
Available in both impermeable and permeable solutions
How Knotweed Root Barriers Work
Japanese Knotweed root barriers work by creating a physical barrier with a signal layer that prevents the growth of Japanese Knotweed roots. The copper in the signal layer causes all plants to avert their growth from it.
These barriers are typically made of durable materials, designed to withstand the aggressive growth of Japanese Knotweed. The barrier is installed around the affected area, effectively containing the roots and preventing them from growing beyond the barrier. This not only halts the spread of Japanese Knotweed but also protects surrounding properties and ecosystems from potential damage.
Types of Root Barriers for Japanese Knotweed
There are several types of root barrier membranes available for Japanese Knotweed, each with its own unique characteristics and benefits. Some of the most common types of root barriers include:
Non-permeable Root Barriers
A reinforced impenetrable root barrier membrane that deflects Japanese Knotweed rhizomes. Used where total containment is required.
Permeable Root Barriers
Allow water and air to pass through while preventing Japanese Knotweed root growth. Used where soil health and drainage is important.
Effective Use of Root Barriers
First identify the area to be protected and prepare the site. Install the barrier to the right depth and orientation so Japanese Knotweed roots can’t grow underneath or around it. Regular checks are important to keep the root barrier intact and working.
Installation Locations For Root Barriers
Root barriers are heavy-duty membranes installed vertically along property boundaries to prevent Japanese Knotweed from spreading between properties. This solution is especially effective in urban areas where properties are close together, protecting property values and preventing neighbour disputes. When used in new construction, root barriers serve as a preventive measure against future knotweed problems.
They can also be used for root barrier capping. Root barrier capping combines horizontal and vertical membranes after removing the most invasive knotweed parts. This creates a contained zone that prevents both upward growth and lateral spread of the rhizomes. The method can be combined with other treatments like herbicides for enhanced effectiveness, providing a long-term solution for managing knotweed infestations.
Cell burial involves creating a deep pit where knotweed-contaminated soil is placed and completely wrapped in a specialized membrane. This contained cell is then buried under clean soil, providing an effective on-site solution when removal isn’t practical. The method prevents regrowth while avoiding costly off-site disposal of contaminated material.
Benefits of Using Root Barriers for Japanese Knotweed Control
Root barriers can save money, resolve legal disputes, and divert waste from landfill when used correctly
They are a physical barrier that prevents Japanese Knotweed roots from growing and spreading
Root barriers can be used to control the spread of invasive plants and prevent damage to property and infrastructure by blocking the growth of knotweed rhizome
