Japanese knotweed

[bennorthyork]

Just on the way into Bradford Interchange and there is a vast amount of Japanese Knotweed on the embankment. Presumably this will damage surrounding buildings. Does anyone know of Network Rail has a plan to tackle this?

 

[DelW]

Do you mean that specific patch, or in general? I'm sure NR have system-wide programmes for vegetation control which will include particular methods for knotweed, which has to be treated differently from other plants. Unfortunately there are fewer and fewer herbicides permitted which can deal with invasive plants (for good reasons, of course).

 

[Shimbleshanks]

Are you sure it's Japanese Knotweed? I had a bit of a scare in my garden a few years ago until I googled it and found there quite a few things that looked like it, but weren't. It includes Lesser Knotweed (Persicaria campanulata); Giant Knotweed (Fallopia sachalinensis)'; Dwarf Knotweed (Fallopia japonica var. compacta); Fallopia x bohemica; and even: Railway-yard Knotweed (Fallopia x Conollyana).

How To Identify Japanese Knotweed: Identification Guide

Find out how to spot Japanese Knotweed using our guide which includes images showing the plan growing throughout the seasons.

www.knotweedhelp.com

 

[bengley]

Are you sure it's Japanese Knotweed? I had a bit of a scare in my garden a few years ago until I googled it and found there quite a few things that looked like it, but weren't. It includes Lesser Knotweed (Persicaria campanulata); Giant Knotweed (Fallopia sachalinensis)'; Dwarf Knotweed (Fallopia japonica var. compacta); Fallopia x bohemica; and even: Railway-yard Knotweed (Fallopia x Conollyana).

How To Identify Japanese Knotweed: Identification Guide

Find out how to spot Japanese Knotweed using our guide which includes images showing the plan growing throughout the seasons.

www.knotweedhelp.com

Network Rail has a significant Japanese Knotweed issue especially in the North - it's highly probable that is is indeed JKW

 

[bennorthyork]

Are you sure it's Japanese Knotweed? I had a bit of a scare in my garden a few years ago until I googled it and found there quite a few things that looked like it, but weren't. It includes Lesser Knotweed (Persicaria campanulata); Giant Knotweed (Fallopia sachalinensis)'; Dwarf Knotweed (Fallopia japonica var. compacta); Fallopia x bohemica; and even: Railway-yard Knotweed (Fallopia x Conollyana).

How To Identify Japanese Knotweed: Identification Guide

Find out how to spot Japanese Knotweed using our guide which includes images showing the plan growing throughout the seasons.

www.knotweedhelp.com

99% sure

 

[Trackman]

Do you mean that specific patch, or in general? I'm sure NR have system-wide programmes for vegetation control which will include particular methods for knotweed, which has to be treated differently from other plants. Unfortunately there are fewer and fewer herbicides permitted which can deal with invasive plants (for good reasons, of course).

And it can take years with approved herbicides to get rid of them.
A relative had them in his garden. Ended up putting a huge membrane down and paid for a new lawn.

 

[Romsey]

When the East London Line was being rebuilt to be part of the LOROL South London Loop, there were serious problems with Japanese knot week at New Cross and New Cross Gate. At one point in the works at New Cross the roots went down three metres and were heading towards then SE mainline. Eventually the whole lot was dug out and shipped off as contaminated waste to a landfill site. I think it worked out at about 200 cubic metres of soil, ballast and roots. The remaining roots in the face of the excavations were treated with herbicide and the whole lot covered in impervious membranes and aggregates.

 

[507020]

99% sure

I have also seen what is certainly Japanese knotweed at several locations in the north, as well as the equally concerning giant hogweed.

And it can take years with approved herbicides to get rid of them.
A relative had them in his garden. Ended up putting a huge membrane down and paid for a new lawn.

How well did that work? Would it even come close to killing the plants?

When the East London Line was being rebuilt to be part of the LOROL South London Loop, there were serious problems with Japanese knot week at New Cross and New Cross Gate. At one point in the works at New Cross the roots went down three metres and were heading towards then SE mainline. Eventually the whole lot was dug out and shipped off as contaminated waste to a landfill site. I think it worked out at about 200 cubic metres of soil, ballast and roots. The remaining roots in the face of the excavations were treated with herbicide and the whole lot covered in impervious membranes and aggregates.

Would it not be better to incinerate that 200m³ of hazardous waste, rather than allow it to continue to grow in landfill?

 

[Trackman]

How well did that work? Would it even come close to killing the plants?

Something happened after that, I can't remember but I will be speaking to him this week so will ask for the outcome.
The main problem was there a large 'colony' of knotweed nearby over a fence - I think he got rid of them too (could be part of the solution). This was about 25 years ago.

 

[Cliveblackpool]

Dreadful plant.
DIY Suggestion - cut it down, leave cuttings there, or if you can burn when dry. wait for it to regrow. When the leaves turn from red to green - plant using maximum energy, cut it again. When regrown red to green, spray (if not close to stream etc) with a good Glyphosate weed killer.
Handle with care. Repeat etc. Takes at least 3 years to confirm it is dead. Co-operate with neighbours. There are strict regulations re disposal - at a tip etc. Inform them by phone before hand that it is JKW.

 

[Bayum]

Dreadful plant.
DIY Suggestion - cut it down, leave cuttings there, or if you can burn when dry. wait for it to regrow. When the leaves turn from red to green - plant using maximum energy, cut it again. When regrown red to green, spray (if not close to stream etc) with a good Glyphosate weed killer.
Handle with care. Repeat etc. Takes at least 3 years to confirm it is dead. Co-operate with neighbours. There are strict regulations re disposal - at a tip etc. Inform them by phone before hand that it is JKW.

And even then, you’ve got the possibility of 20 years for any of the root system/rhizome not destroyed to spring back to life.

 

[InOban]

You don't spray with glyphosate, you inject it into the stems.
There's a new method being trialled successfully. You need a generator and two electrodes. One is plunged into the soil next the roots. The other is inserted into the stems. The current boils the plant down to the roots.

 

[thejuggler]

The knotweed alongside that route has been there at least 20 years. It will never be eradicated as NR won't have time or resources to tackle it properly.

Adjacent landowners may complain, but damage to buildings by knotweed is overstated and property treating small areas which may be affecting adjacent properties is far easier.

 

[Cliveblackpool]

You don't spray with glyphosate, you inject it into the stems.
There's a new method being trialled successfully. You need a generator and two electrodes. One is plunged into the soil next the roots. The other is inserted into the stems. The current boils the plant down to the roots.

Thank you InOban - Agree inject it - stems are hollow.
New method should be the answer - no poisonous chemicals!

And 20 years is a possibility - thank you Bayun.
Do not dig anywhere near it - 7m ? 1 cm of root/ stem can grow into a new plant. That's how it spreads.

 

[judethegreat]

I have it in my garden.
Landlord takes almost no responsibility, much to the consternation of the home owning neighbour... I don't mind too much though for the dogs' sake..
Since being treated either side however i have found it is much reduced in our garden. What i also read, before it was being treated either side, and have found to work, was that if you cut each stem down to two to four inches above the ground, it stops it spreading. Takes longer to eradicate this way (read ten years..) than using chemicals, but obviously much more preferable. This then leaves opportunity to also be injected with poison later, with much less amount of toxic plant for bees and such like to land on and die (JK is apparently very attractive to bees, though not noticed it myself). Just DO NOT DIG - it is the roots being disturbed that makes it go mental.
Really pleased to read above of that new alternative treatment method.
On the plus side, the stems can be eaten, raw or cooked. Very similar to rhubarb in taste, behaviour when being cooked and nutritional value. My mate referred to it as "funky rhubarb"! Best used when fresh and soft, otherwise can be quite woody and/or stringy. Apparently the roots are used in Chinese medicine, though for obvious reasons we should not be harvesting them, unless i guess it is grown (and strictly kept) in pots... And best not consume any of it once it has been treated with glyphosate..

 

[yorksrob]

There's a potential answer to the cost of living crisis - knotweed crumble !

 

[judethegreat]

There's a potential answer to the cost of living crisis - knotweed crumble !

I have actually made that...and cheesecake...thoroughly recommended...

 

[yorksrob]

I have actually made that...and cheesecake...thoroughly recommended...

I'm intrigued - although I'm not much of a cook myself.

 

[Trackman]

.., unless i guess it is grown (and strictly kept) in pots... And best not consume any of it once it has been treated with glyphosate..

Isn’t it illegal to grow it?

 

[judethegreat]

I'm intrigued - although I'm not much of a cook myself.

As i said, just use it as if its rhubarb, taking care obviously to make sure not a trace of it ends up in normal compost or whatever. Also i have added it to salads.

Isn’t it illegal to grow it?

Probably, i wasn't necessarily advocating doing it.

 

[341o2]

Thank you InOban - Agree inject it - stems are hollow.
New method should be the answer - no poisonous chemicals!

And 20 years is a possibility - thank you Bayun.
Do not dig anywhere near it - 7m ? 1 cm of root/ stem can grow into a new plant. That's how it spreads.

Another method - as soon as it is cut down, paint the raw stump with weedkiller.
Apparently goats love it

 

[Pinus contorta]

I know the pigs would have a go at it where i used to work. Although probably not when it is several foot above their head. I've seen there is also a market for using grazing pigs for rhododendron control.

 

[judethegreat]

I have been told i should get a goat or similar...but minus the weedkiller...

Remember hearing of a case of it growing in one small location alongside a major trunk road, possibly the A43 but not sure now, along comes the tractor hedge trimmer thingy and scatters it, it now grows along a huge stretch...

 

[341o2]

There is a specialist firm that also deals with other invasive species, it received over 12,000 callouts last year.

Japanese knotweed roots can go through virtually anything including invading the interior of buildings, and disturbing foundations.

It flowers in Summer, the above mentioned hedgecutting probably spread seeds. I have also heard that cutting back and the application of weedkiller should be done immediately after flowering when the plant is beginning to die back.

 

[Pinus contorta]

I believe its native habitat, before it was 'discovered' by the victorians and carted round the world, is colonising in proximity to larval flows. It would need to be pretty resilient to be able to establish there where not much else can get a foothold. That's why it's characteristics include being able to break through concrete.

 

[InOban]

AIUI, there are no seeds. Fortuitously, only the male plant was imported into the UK. There have also been trials with a scale insect which only lives on it.

 

[Darandio]

AIUI, there are no seeds. Fortuitously, only the male plant was imported into the UK. There have also been trials with a scale insect which only lives on it.

Any academic paper on the plant over the years that I have read suggests all japanese knotweed present in the UK originated from a single female clone.

 

[InOban]

You're probably right. I just knew that they were all the same sex, so no seeds.

 

[judethegreat]

Interesting about it growing in and around larval flows hence it's hardiness - hadn't read that before, thanks. Knew in its natural climate it faced more resistance so was kept in check.
There was something a few years ago about it not being quite as bad as thought, i.e. it won't actually break through concrete etc, rather just exploit cracks and other weaknesses it may find; otherwise stick with the path of least resistance i.e. open soil etc.

 

[thejuggler]

There is a specialist firm that also deals with other invasive species, it received over 12,000 callouts last year.

Japanese knotweed roots can go through virtually anything including invading the interior of buildings, and disturbing foundations.

It flowers in Summer, the above mentioned hedgecutting probably spread seeds. I have also heard that cutting back and the application of weedkiller should be done immediately after flowering when the plant is beginning to die back.

I have years experience of his plant and like all scare stories some people have become very rich on it. I've been at conferences with 'specialists' and they are the ones arriving in the Porsche and Bentleys! I know one company buying a factory that had three small areas along the back wall. The specialist quoted £12,000 for 'specialist' treatment and insurance. Local licensed landscaper I used charged £1,000 in year one for four visits to spray and £200 for each subsequent visit. It was gone after three years.

The plant was imported by Victorian botanists for collections for Kew gardens etc. Ironically it was found to be very good at binding soil and was planted on railway embankments. Now it is out of control in many areas.

It grows using a network of rhizomes, like ginger and turmeric roots, which grow underground and the plant then grows shoots which look like bamboo around this time of year. The flowers in September aren't for reproduction. The plant then dies back over winter, the rhizomes grow over winter and it spreads over the years.

A plant which is left untouched can remain small for many years, go and hack it and the rhizomes will spread further. Getting animals to eat it is a bad move, the rhizome fragments will be spread with their waste and one small piece will be a plant inside a year.