- CONDITION 17 - JAPANESE KNOTWEED
17. No development shall commence until a detailed up-to-date survey of the presence of
Japanese Knotweed within both the site and its vicinity shall be carried out. A resulting
scheme for the control of Japanese Knotweed on site, and its eradication from the site,
shall be submitted to and approved in writing by the Local Planning
the development shall be carried out in accordance with that scheme.
REASON: Under the Wildlife and Countryside Act 1981 (as amended) it is an offence to
plant Japanese knotweed or otherwise cause it to grow in the wild. This species has
been identified on site and is ecologically and structurally damaging. It must be controlled
to prevent its spread both during and after construction, and eradicated from the site
(with appropriate disposal as necessary) having regard to Policy EN8 of the adopted
Wealden Local Plan. With regard to Regulation 35 of the Development Management
Procedure Order 2015, it is essential to ensure the eradication of this invasive species
from the site prior to construction works, therefore the condition adopts the
format to protect the environment.
THAKEHAM, CLARION (GROUP) - LIST OF PERSONS INVOLVED IN THE DEVELOPMENT
Rawlinson - Gleeson Strategic Land
Rainbow - Arboricultural & Biodiversity Officer
- Managing Director, Thakeham Client
Richard White, Director of Land and Planning at Latimer
& Clarion Housing Group
DEVELOPMENTS - Previously: William Sutton Developments Limited
Water - Nick Claxton Team Manager – Flood Risk Management & Revai Kinsella, Principal Drainage Officer
HERSTMONCEUX VILLAGE CONDITIONS A - Z INDEX
Japanese knotweed flowers are valued by some beekeepers as an important source of nectar for honeybees, at a time of year when little else is flowering. Japanese knotweed yields a monofloral honey, usually called bamboo honey by northeastern U.S. beekeepers, like a mild-flavoured version of buckwheat honey (a related plant also in the Polygonaceae).
The young stems are edible as a spring vegetable, with a flavour similar to extremely sour rhubarb. In some locations, semi-cultivating Japanese knotweed for food has been used as a means of controlling knotweed populations that invade sensitive wetland areas and drive out the native vegetation. It is eaten in Japan as sansai or wild foraged vegetable.
It is used in traditional Chinese medicine and traditional Japanese medicine to treat fungal infections, various skin inflammations, and cardiovascular diseases; one active ingredient is thought to be resveratrol and its glucoside
Japanese knotweed has a large underground network of roots (rhizomes). To eradicate the plant the roots need to be killed. All above-ground portions of the plant need to be controlled repeatedly for several years in order to weaken and kill the entire patch. Picking the right herbicide is essential, as it must travel through the plant and into the root system below.
The abundance of the plant can be significantly reduced by applying glyphosate, imazapyr, a combination of both, or by cutting all visible stalks and filling the stems with glyphosate. However, these methods have not been proven to provide reliable long-term results in completely eliminating the treated population.
Digging up the rhizomes is a common solution where the land is to be developed, as this is quicker than the use of herbicides, but safe disposal of the plant material without spreading it is difficult; knotweed is classed as controlled waste in the UK, and disposal is regulated by law. Digging up the roots is also very labour-intensive and not always efficient. The roots can go to up to 10 feet (3.0 meters) deep, and leaving only a few inches of root behind will result in the plant quickly growing back.
Covering the affected patch of ground with a non-translucent material can be an effective follow-up strategy. However, the trimmed stems of the plant can be razor sharp and are able to pierce through most materials. Covering with non-flexible materials such as concrete slabs has to be done meticulously and without leaving even the smallest splits. The slightest opening can be enough for the plant to grow back.
More ecologically-friendly means are being tested as an alternative to chemical treatments. Soil steam
sterilization involves injecting steam into contaminated soil in order to kill subterranean plant parts. Research has also been carried out on Mycosphaerella leafspot fungus, which devastates knotweed in its native Japan. This research has been relatively slow due to the complex life cycle of the fungus.
Two biological pest control agents that show promise in the control of the plant are a leaf spot fungus from genus Mycosphaerella and the psyllid Aphalara itadori. Research has been carried out by not-for-profit inter-governmental organisation CABI in the UK. Following earlier studies imported Japanese knotweed psyllid insects (Aphalara itadori), whose only food source is Japanese knotweed, were released at a number of sites in Britain in a study running from 1 April 2010 to 31 March 2014. In 2012, results suggested that establishment and population growth were likely, after the insects overwintered successfully.
Anecdotal reports of effective control describe the use of goats to eat the plant parts above ground followed by the use of pigs to root out and eat the underground parts of the plant.
Detail of the stalk
The most effective method of control is by herbicide application close to the flowering stage in late summer or autumn. In some cases, it is possible to eradicate Japanese knotweed in one growing season using only herbicides. Glyphosate is widely used as it is non-persistent, and certain formulations may be used in or near
In the UK, Japanese knotweed is established in the wild in many parts of the country and creates problems due to the impact on biodiversity, flooding management and damage to property. It is an offence under section 14(2) of the Wildlife and Countryside Act 1981 to "plant or otherwise cause to grow in the wild" any plant listed in Schedule nine, Part II to the Act, which includes Japanese knotweed. Within towns householders and landlords in 2014 who did not control the plant in their gardens could receive an on-the-spot fine or be prosecuted. It is also classed as "controlled waste" in Britain under part 2 of the Environmental Protection Act 1990. This requires disposal at licensed landfill sites.
The species is expensive to remove. According to the UK government, the cost of controlling knotweed had hit £1.25 billion in 2014. It cost £70 million to eradicate knotweed from 10 acres of the London 2012 Olympic Games velodrome and aquatic centre. Defra's Review of Non-native Species Policy states that a national eradication programme would be prohibitively expensive at £1.56 billion. The Centre for Ecology and Hydrology has been using citizen science to develop a system that gives a knotweed risk rating throughout Britain.
The decision was taken on 9 March 2010 in the UK to release into the wild a Japanese psyllid insect, Aphalara itadori. Its diet is highly specific to Japanese knotweed and shows good potential for its control. Controlled release trials began in South Wales in 2016.
In Scotland, the Wildlife and Natural Environment (Scotland) Act 2011 came into force in July 2012 that superseded the Wildlife and Countryside Act 1981. This act states that is an offence to spread intentionally or unintentionally Japanese knotweed (or other non-native invasive species).
In the north-east of Ireland it has been recorded from Counties Down, Antrim and Londonderry. The earliest record is in 1872.