Japanese Knotweed Specialists - Identification & Control in Ware, Hertfordshire
As Japanese Knotweed Identification, control and treatment specialists, Perfect Ground Solutions speak to many worried land owners, government offices and commercial establishments about the affect Knotweed has on garden maintenance, new-builds and grounds maintenance. So we’ve written this guide to shed some light on all-things Japanese Knotweed.
Japanese Knotweed Identification
Japanese knotweed can be identified as a tall, vigorous ornamental plant, that originally escaped from cultivation in the late nineteenth century to become an aggressive invader in the urban and rural environment.
Japanese knotweed’s scientific names include:
- Fallopia japonica (Houtt. Ronse Decraene)
- Reynoutria japonica (Houtt.)
- Polygonum cuspidatum (Siebold & Zuccarini)
Japanese Knotweed is a member of the dock family (Polygonaceae) and is a rhizomatous (produces underground stems) perennial plant with distinctive, branching, hollow, bamboo-like stems, covered in purple speckles, often reaching 2-3 m high.
The leaves of a mature plant can grow up to 120 mm in length, with a flattened base and pointed tip and are arranged on arching stems in a zig-zag pattern.
Japanese Knotweed flowers late in the season, August to October, with small creamy-white flowers hanging in clusters from the leaf axils (point at which the leaf joins with the stem).
The underground rhizomes are thick and woody with a knotty appearance and when broken reveal a bright orange-coloured centre. The rhizome system may extend to, and beyond, a depth of at least 2m and extend 7m laterally from a parent plant. During winter, the leaves die back to reveal orange/brown coloured woody stems which may stay erect for several years. Stem and leaf material decomposes slowly, leaving a deep layer of plant litter. During March to April, the plant sends up new shoots, red/purple in colour with rolled back leaves. These shoots grow rapidly due to stored nutrients in the extensive rhizome system. Growth rates of up to 40 mm a day have been recorded.
Only female Japanese knotweed (F. japonica var japonica) plants have been recorded to date in the UK.
Two species closely related to Japanese knotweed are also found in the UK:
- Giant knotweed (Fallopia sachalinensis), a much taller plant which reaches a height of 5m
- A smaller compact variety (Fallopia japonica var. compacta) which grows to a height of only 1m
The hybrid (Fallopia x bohemica) (a cross between Japanese knotweed and giant knotweed) is also found throughout the UK but is not as common as Japanese knotweed. Both giant knotweed and the hybrid react to the same methods as used for Japanese knotweed control.
Japanese Knotweed Control
It is worth noting that from a legal perspective, it is not an offense to have Japanese knotweed on your land and it is not a notifiable weed. Allowing Japanese knotweed to grow onto other people’s property may be regarded as a private nuisance under common law and this would be a civil matter.
Although there are a number of non invasive options available for controlling Japanese Knotweed it should be noted that they take a number of years in order to be effective.
There are several herbicides that are cleared for use by Japanese Knotweed specialists, the choice of chemical will depend on the type of area, surrounding plants and proximity to water courses.
As specialists, our Knotweed services involve investigating your Knotweed problem and reporting on the best way forward to make sure you receive the most suitable and cost effective solution.
Japanese Knotweed Treatment Contractors
Japanese Knotweed treatment using herbicides is a tried and tested method of removing this plant. It is not instant and needs to be carried out by contractors who have an understanding about how the plant grows and how and when to apply which herbicides.
The method of application is also important. Stem injection is an ideal method of application as it concentrates the chemical where it is needed and removes the risk of over spraying neighbouring plants.
Most successful results from the use of herbicides occur from treatment in late summer and early autumn as the Knotweed is drawing nutrients, and hence the herbicide, down into its root structure before it dies back for the winter. It is imperative that during the treatment program, the Knotweed and its surrounding area should remain undisturbed. This is not only to ensure that each application of herbicide is as thorough as possible but also to prevent the Knotweed from spreading.
If you need help identifying, treating or controlling Japanese Knotweed, please contact us to arrange an informal visit. Alternatively read our latest news, find out more about us or sign up for our email newsletter.
Author: Colin Peters