As the title suggests, a neighbour kindly pointed out the above situation this evening. I think the house is rented out, what’s the best course of action, landlord or council?

Why did would the knotweed cross the road?

Kill it with fire. Kill it to death.

I’m sure I heard someone claim that there’s only one knotweed plant in the whole of the UK. It’s all cutting of one from whenever it first come into the country.

Im very sure they didn’t plant it.
Theres probably not a lot you can do as its not on your property.

Some useful info here and here. It looks like it’s between you and your neighbour unless it is spread into the wild or an adjoining garden, at which point it seems to be something of an offence

andyl suggestion is best, but not guaranteed.

Not experienced that, but we have Sumac or a Vinegar tree and it’s probably nuke proof.

I spent 2 years pulling the shoots out to no avail. The only thing that seemed to work was the most toxic weed killer, mixed double strength and injected using a large syringe and needle directly into whatever bits I couldn’t strip out.

That’s three days crawling on the lawn with bike knee pads following the line of any and every root, ripping up the lawn and hosing weed killer everywhere. Looked like the garden had been stripped of varicose veins….

But it seems to have worked…

You should contact the landlord/agent. Sadly I am not sure there is much you can do legally to oblige them to deal with it. You may be best served to sort it out for them with their permission and taking care how you do it. Even if this is at your expense you’d be best served to deal with it on their land before it gets to yours

I’m currently waging a one man war on Knotweed in our (partly) and our neighbours (mostly) gardens.
Agricultural strength neat Glyphosate (roundup) is doing the trick, just pop out into the garden twice weekly and liberally daub it on to anything our side of the fence!
I’ve taken to pouring it over into the neighbours garden which also appears to be making some progress.
It certainly seems less keen to poke its little head above ground level now, but I expect it will be a long term exercise to rid it completely.

Whilst it is by no means impossible I would doubt that your neighbours knotweed would come under the road, but it does go down a LONG way (3m I think!).