Possibly the evil plant!

[Didactylos]

Ive posted this on gardening but thought I should put it on Property as well for the traffic and potential advice
I recently moved into a house which has a small blind ending back lane, shared privately between the houses that back onto it. Was putting out the bins the other night and noticed some plants growing in the lane that appeared to be an extension from a plant in the back garden facing ours , (eg under their fence, on the other side of the lane) and out of idle curiosity took a few pics as I couldn't identify it and it seemed pretty vigorous and fast growing.

Im sure you guess where this is going - Im about 99% certain that its Japanese knotweed, (timing of shoots, images, leaf shape etc all match and its not any plant I know that grows well wild here eg lilac, dogwood etc)
It seems to be established in the other garden (shared carpack/garden of a low rise block of flats) and has sent up shoots on the other side of the fence. This is at the end of the back lane, its about 10 metres from our property but closer to the flats, and close to another building that sits across the top of the lane (sheltered housing)

I wasn't sure what to do about it - my initial thought would to get someone round to confirm my suspicions and that if I am correct eradication would be best, but its on someone else's property (the shared flats) and the back lane is not ours alone but owned in common between about 8 houses, including the flats. I am not sure if the sheltered housing has any right of access or maintenance for the lane but they are the closest to the plants (about 2-3 metres from their wall) and so probably need to know about them too.
Initially I planned to go and talk to some of the neighbours? flats and sheltered complex´management, and then the others, explaining the issue and seeing if we could make a shared plan to get these plants checked, and potentially eradicate them. Should I offer to share costs: or would it be the responsibility of the flats on whos ground the knotweed is established and from where its sending out shoots?

any experiences and thoughts welcome,

[wowfudge]

The land owner from where the JK is growing is responsible for dealing with it. There is no reason you should pay anything towards its control and eradication. Contact the council for advice. Check that it isn't bindweed - the leaves can look very similar, especially on shoots.

[kernowgal]

Can you post a pic here, OP? As wowfudge says, bindweed can be quite similar although it uses other plants to climb whereas knotweed is self-supporting.

But yes, whoever owns the flats is responsible for sorting it out.

[Didactylos]

will see if I can get the pictures off my phone and post on here, but as I said Im 99% sure, got reasonable interest in plants and some training in biology and identification:
its definitely not bindweed of any sort: self supporting canes, green and red speckled, a bit like bamboo, leaves unfurling, bright green and heartshaped along the stalks alternately. On the other side of the fence the plant is about 2 metres tall already, these shoots are about 1 metre tall

[concertplayer]

There are companies advertising JK services.You can send them pics and they
will be able to advise if it jk or not. You don't really want to fall out with the
neighbours in the flats so perhaps tell them before you go to the Council etc?
I had a look for you on RICS/RHS and they do advise telling the neighbours
but that does not mean you have to pay.
If you do, you may be doing them a favour as they could be unaware
of it and/or if it spreads elsewhere they will be liable .

[Didactylos]

ok, went to speak to the people in the flats who's ground the plant is on as a starting point
didn't realise but its owned by a religious order and all the flats are occupied by their nuns. The nun I spoke to said they had had issues years before and would get on to the factor and estate manager of the building and have someone out to look at it so they seem very keen to take it seriously
might send my pictures off to one of those sites as well, ill feel stupid if im wrong!

interesting! often wondered why the neighbours were so quiet.....

[Didactylos]

im sure nuns wont start a neighbourly vendetta, will they? Scared now....

[concertplayer]

Do not be scared As previously advised you may have done them a favour.
If it spreads they could be sued and it end up costing £££££. more in the end.
Much better to deal with it now.

[Adarajames]

I want nuns as neighbours! Sure would be far more peaceful than the neighbours I do have! /misses point of thread/