Japanese Knotweed in Nunhead

[werdna101]

At the weekend we finally got out in the garden and noticed that quite a bit of Japanese knotweed had sprung up in our garden. Looking around we also noticed it in the neighbours' gardens, and then this morning it is all along the embankment at Nunhead station.

Anyone else in the Nunhead area found any?

Any tips for how to deal with it?

[Jeremy]

It's a huge problem around Nunhead, ED, Peckham, etc. Especially near railway lines and industrial/commercial land.

For any Knotweed on Network Rail property, you need to contact Network Rail immediately and they should deal with it. They have teams dedicated to this sort of thing, and have access to specialist herbicides.

For any on your own property, you can either call in specialists or deal with it yourself. If you're dealing with it yourself, the most effective solution seems to be

- Wait until the stems are wide, hollow, and resemble something between rhubarb and bamboo

- Cut them down to 1-2 ft

- Break down the internal structure of the stem with a thin rod (without puncturing the outside of the stem)

- Fill it up with a concentrated glyphosate solution

[Whittler]

That's really good advice, Jeremy....

Best to use the glyphosate in late summer, and if you do dig any live rhizomes out, you need to dry them and burn them, not dispose of them in general waste. More info here:

http://www.environment-agency.gov.uk/homeandleisure/wildlife/130079.aspx#How_to_control_Japanese_knotweed

It'll take about 3 yrs to clear any one site, but a combination of removal by digging and herbicide should do it.

[TopTree]

Can you post a picture of what it looks - like - Please?

[Jeremy]

Some good pics on the wikipedia page. This one is a good closeup.

http://en.wikipedia.org/wiki/File:Knotweed.JPG

The red and green cane-like stem is a giveaway at this time of year. Later in the year, the bunches of small white flowers will be another obvious sign.

[benmorg]

werdna101 Wrote:

-------------------------------------------------------

> At the weekend we finally got out in the garden

> and noticed that quite a bit of Japanese knotweed

> had sprung up in our garden. Looking around we

> also noticed it in the neighbours' gardens, and

> then this morning it is all along the embankment

> at Nunhead station.

>

> Anyone else in the Nunhead area found any?

>

> Any tips for how to deal with it?

+1 from Jeremy. I would make a written complaint to Network Rail about any affected land near your property. They will then spray or inject the plants.

Regarding the plants on your own property, I would advise dealing with it yourself. Glyphosphate does work, but it takes a few years of killing every shoot before the roots are dead. You'll need to speak to your neighbours to treat their plants too.

A better chemical to use is picloram. It works like glyphosphate, but unlike glyphosphate it remains active in the soil for several years, so it can destroy a knotweed stand in one application. You need a license to use picloram, so it means getting a knotweed eradication company in.

Don't believe all the alarmist nonsense about knotweed threatening buildings or being impossible to kill. It's easy to kill (though can take a few years) and poses no threat to buildings. The two big problems are: 1) it's classified as controlled waste, which means there are strict rules about how to get rid or it; and 2) a lot of banks won't grant mortgages on property affected with knotweed (because of 1).

[werdna101]

Thanks for the advice. Can anyone recommend any good local companies that deal with it effectively? Anyone had any good or bad experiences?

[KestonKid]

Not quite sure that knotweed is no threat to buildings. Our insurance company takes a dfferent view about the weed in our our two neighbours' gardens and asked me to contact their housing associations to suggest that they took action. This duly took place (twice) last year - a contractor came and injected it all - yet it has now reappeared and further treatment is being arranged.

[Jeremy]

Yeah I think whatever method you use, it is generally accepted that complete removal takes at least a couple of years.

[benmorg]

KestonKid Wrote:

-------------------------------------------------------

> Not quite sure that knotweed is no threat to

> buildings. Our insurance company takes a dfferent

> view about the weed in our our two neighbours'

> gardens and asked me to contact their housing

> associations to suggest that they took action.

> This duly took place (twice) last year - a

> contractor came and injected it all - yet it has

> now reappeared and further treatment is being

> arranged.

The threat is wildly exaggerated. Lots of plants can damage drains or walls, especially trees. Knotweed is no more a threat to buildings than buddleia and much less of less of a threat than tree roots. It is a massive problem for commercial developers though as it's incredibly expensive to eradicate over short timescales (they have to excavate vast amounts of contaminated land, sieve all the soil, and dispose of the knotweed in government-approved controlled waste sites). In domestic situations it really isn't such a big deal if you have a few years to keep spraying. Definitely a headache if you need to get a mortgage or sell a property.

The knotweed eradication companies love spreading the scare stories as they're great for drumming up business. They will tell you that it's a job for the pros and mustn't be undertaken by amateurs - and will then charge ?300 a day for spraying with glyphosphate. Which of course doesn't kill the plants in one year, so the company has to come back for 3-5 years on the trot.

[benmorg]

werdna101 Wrote:

-------------------------------------------------------

> Thanks for the advice. Can anyone recommend any

> good local companies that deal with it

> effectively? Anyone had any good or bad

> experiences?

I would suggest getting at least three quotes. Insist they use picloram rather than glyphosphate (not always possible - depends on the local environment) and ask what kind of guarantee they provide and how many years it lasts. Avoid any company that doesn't promise to come back the following year(s) to treat regrowth.

[Penguin68]

Reality and what insurance companies think is rarely aligned - insurance companies think that if you have repaired damage caused by subsidence and underpinned your building it is at greater risk, so charge higher premiums - insurance companies think that if you are near a river even when you are on a bluff more than 20 ft above the highest point of the bank - then you are a flooding risk (yes, really) - and won't insure or charge higher premiums - indeed insurance companies in general look either to avoid liability or to - you've got it, charge higher premiums.

Any fast growing plant with slightly woody stems can cause superficial damage - knot-weed is not going to bring your house down. It will come up through paving (so will grass). It does take time to kill-off - most sources suggest you need 3 growing seasons of poisoning to do it. Choosing a herbicide which stays active in the soil is fine if you are to build over the site of infestation - but not if it's part of a garden in which you want to grow things.

[benmorg]

Penguin68 Wrote:

-------------------------------------------------------

Choosing a

> herbicide which stays active in the soil is fine

> if you are to build over the site of infestation -

> but not if it's part of a garden in which you want

> to grow things.

That's definitely a factor in choice of herbicide. Picloram will kill any broadleaved flowering plant that tries to grow for about two years. It's harmless to grass through, so a lawn is OK. Also conifers, ferns, etc. are immune to it, and animals are unaffected.

[KidKruger]

Are hedges immune ?

I have some knotweed in my hedge !

[benmorg]

KidKruger Wrote:

-------------------------------------------------------

> Are hedges immune ?

> I have some knotweed in my hedge !

No, picloram will zap the hedge or at least part of it. If it's a small amount of knotweed, do it yourself with glyphosphate.

Going back to the original post - if the knotweed appears to come from land owned by network rail, I would get them to eradicate the plants on your property too as it's their fault that the infestation spread. They would almost certainly do all the work at their cost.

[Dr De Soto]

If you find knotweed on your property, aren't you obliged to notify Southwark Council? That was our understanding when we had some. As I recall, best time of year to treat it is September/October.

[Jeremy]

KK, I believe the injection or stem filling method is safe to use when you want to protect surrounding plants.

[GEEKASAURUS]

I have buckets of this plant spreading along the ground (doesn't grow upwards unless climbing on something). The leaves look different to JK. Does anyone know what it is so I can stop worrying about it?

Cheers

[intexasatthe moment]

Not JKW - looks like bindweed .

http://apps.rhs.org.uk/advicesearch/Profile.aspx?pid=241

[GEEKASAURUS]

thank you!

[Whittler]

Yep, that's bindweed alright.... it'll take over very, very quickly, but fairly easy to eradicate (compared to JKW) with a glyphosate product (eg. Roundup). Best thing to do if it's going along the ground is pop some canes in and let the plant grow up them then you can spray the leaves with the glyphosate - best to do it on a clear day like today. Should do the trick. Easy to dig out as the roots are white and pretty visible in the ground.

[KidKruger]

GEEK - it may just be some kind of ground covering / climbing weed. If you tug on it, are it's roots forming an incoherent web a few inches underground ? If so possibly bindweed. Another bindweed indicator is when you try to pull the stalks out of the ground, this 'sleeve' pulls off but the core is left above ground, so you have to dig it out.

[ironjawcannon]

Network Rail phone number is 08457114141 for railside related knotweed infestation. By the way you can eat the small sprouts of knotweed when they look a bit like asparagus. boil them and they taste a bit lemony. However it is certainly not a reason to keep growing the beastly stuff!

[george74]

There is a specific 'code of practice' for dealing with Japanese Knotweed so would recommend you speak to the Council and Environmental agency before removing, as it needs to be taken away and contained; usually by specialist companies.

Good luck!

[Ginster]

Hi werdna101,

I had an issue with Knotweed last year when trying to sell my flat in Copleston Road (interestingly I was on the other side from the railway). I wasn't aware I had it until the survey was done by the buyer's mortgage company who somehow spotted it at back of garden (60ft from house) and refused to offer a mortgage on the flat.

Much fun ensued... it was 50/50 on my land and neighbours and thankfully they agreed to pay half the removal/treatment fee.

Buyers found a new (worse %age) mortgage so knocked money off their offer AND I had to pay my half of the treatment cost - fun times!

I used TP Knotweed who were very good - lots of good write-ups online and they seem to be at the forefront on research and work into the plant. They offer a 5-year treatment plan (which I of course no longer have any involvement in, it was handed to the buyers). It means they treat, remove and will be available to re-treat if required in the next 5 years. It was enough for the buyers new mortgage company to accept thankfully!

Per what others say - if you're right near a train line (that is where it is often rife I read) then definitely see if you can get anything out of National Rail as they should bear some of the cost!

I'm amazed there isn't more known out there about this plant as I am sure so many people must just cut it down like any other plant they don't want and dispose of - when there are actually strict rules (and I believe fines) for not disposing of this properly. I had never heard of it until I had it.

Good luck!