noxious & invasive weed control

The invasive plants division of Down to Earth provides control and plant removal services throughout South East London and Kent. Our specialist contractors are fully trained and hold all relevant certifications utilising the most current control equipment and processes.

What is Japanese Knotweed?

Japanese Knotweed is a strong-growing, clump-forming perennial, with tall, dense annual stems. Stem growth is renewed each year from the stout, deeply-penetrating rhizomes (creeping underground stems). Japanese Knotweed was introduced from Japan in 1825 as an ornamental plant. The plant is not unattractive but its rapid annual growth and relentless spread, allows it to easily overwhelm other garden plants. Where established as a wayside weed, native plants are also aggressively over-run.

Legislation

Although it does not produce seeds, knotweed can sprout from very small sections of rhizomes and, under the provisions made within the Wildlife and Countryside Act 1981, it is an offence to cause Japanese Knotweed to grow in the wild. Much of its spread is probably via topsoil movement or construction traffic.
An amendment to the Anti-social Behaviour, Crime and Policing Act 2014 includes Japanese Knotweed and other invasive non-native plants.

Chemical Control

The most cost effective method of controlling Japanese Knotweed is with a targeted application of strong herbicide over a period of time.

Effective removal can be difficult, as even small parts of the plants’ rhizome (rooting system) can harbour enough energy resource to rapidly develop into a new crop, and the use of retail weed killer is rarely effective as it can take several seasons to establish whether your efforts are successfully managing the plant.

Down to Earth provide a considered approach and bespoke project plan for each site starting with the initial stage of positive identification through to the appropriate disposal of the dead plant.

Using specialist stem injection equipment, you will be able to notice an effect within two weeks of our initial application visit and, through periodic site monitoring, our goal is to have your Japanese Knotweed problem contained and controlled as soon as possible.

Do I have Japanese Knotweed?

The best time to spot Japanese knotweed is during mid-summer and early autumn. The key distinguishing features are the red speckled stems and reddish shoots with a zig-zag growth pattern. The large broad leaves have a distinct flat base which is perpendicular to the petiole (leaf stem).

What are the Different Impacts of Japanese Knotweed?

Environmental Impact

Perhaps the most distasteful aspect of the Japanese knotweed problem is its aggressive, all-conquering nature. It spreads quickly and forms dense colonies that block the sun to other plants, suck water from the soil and hoard nutrients, while just below the surface the rhizomes spread quickly. If left untreated other plants in the area soon succumb to the onslaught.

Knotweed plants can be uprooted and transported miles away during floods, quickly taking hold where they come to rest and creating new colonies. When these invasive weeds take root in riverine systems they can interfere with the normal flow of water, and during heavy rain events, increase the risk of flooding.

Curiously, Japanese knotweed does a poor job spreading via seeds. First, because it does not produce a high volume of seeds and second because the seeds it does produce tend to get damaged by frost, eaten by birds or shrivel and die in dry soil conditions. Because of this, we can conclude that these invasive plants spread primarily via human activity, i.e. construction work, road maintenance and the like.

Community Impact

If this were some kind of aesthetic wonderplant, removing Japanese knotweed might not be such a priority. But in fact, it is quite the ugly duckling. The above-ground portion dies off during the cold weather months leaving unsightly thick, bare stalks. Even at its best, the plant has a weediness about it that has people calling our Japanese knotweed removal service.

Perhaps worst of all is that the dead stalks tend to catch trash blowing on the wind and low to the ground stalks often attract rats and other vermin necessitating removal work. In areas where Japanese knotweed penetration is significant, the stands are often used to hide nefarious activities. As a result of all these factors and more, Japanese knotweed can have a significantly negative impact on communities where it is left untreated.

Structural Impact

The rhizome systems of Japanese Knotweed have been known to undermine the integrity of structures such as sidewalks, roads and foundations. As it forces its way into these areas the rhizomes grow in size and expand upward, producing cracks in sidewalks, parking lots and roads. The rhizomes of the Japanese knotweed plant can also damage water pipes, septic tanks and foundations. We highly recommend professional Japanese knotweed removal, lest the untrained unwittingly spread the plant during attempted removal work.

Japanese Knotweed contractors

Japanese knotweed identification is not always easy. If you are still unsure whether you have a case of Japanese knotweed on your property please send us a photograph for a free assessment, ideally including a close-up of some leaves if possible, to enquiries@dtetrees.co.uk. If you do have knotweed, then one of our consultants would be happy to help. In the meantime, avoid cutting or pulling up the plant where possible as it has a negligible effect on the plant and makes successful treatment more difficult.