Japanese Knotweed how bad is it?

[what..the?]

just moved into a Japanese Knotweed area it seem to flourish in the public areas which surely the council should control but it is coming into our garden the neighbour says he had a garden full and he has almost got rid of his and now he has laid paving. I have yet to tackle....tackle being the appropriate term for this jungle which is our new garden. But would like to know what people think of Japanese Knotweed I get the impression some people over exagerate how bad it can be, so would like peoples views on the little devil?

Thanks in advance.

[landscaper2]

Not a nice weed, can be treated with continual doses of Roundup, but will take a few years. If some is on Council land as you say, I would think they are duty bound to eradicate the problem on their side.
I also believe that it is a notifiable weed that should be disposed of by incineration and not by digging out and put into a normal skip.
Left untreated it WILL take over your garden - as you have probably seen

[ChuckFickens]

Left untreated I wouldn't expect the neighbours paving to last very long! that stuff will break through most things in time.

[carrot99]

I'm in SE London and have had it for over 30 years. I used to just keep cutting it down but left a line of it across the bottom of the garden as it is quite attractive when fully grown, with little cascades of tiny white flowers. It also hid the neighbours at the back as it grows to 7 or 8 feet tall.

I believe the main problem with it is that it's broad leaves stop anything from growing below by blocking the light and not to mention the fact that it marches across gardens, respecting no boundaries.

Last year I had it sprayed with something strong by a professional gardener and this year it has returned in a mutated form - instead of tall poles with broad leaves it is coming up in very short, dense clusters with tiny little leaves. So I'm waiting to see if it dies out completely or recovers next year.

[landscaper2]

Probably not done for yet I'm afraid Carrott, further treatments should work, may be 3-4years tho.

[brifos]

Haven't had it myself but a recent article I read was from soneone who lets it grow a while then cuts it down to about a foot high and drips Roundup into the hollow stalk.

[what..the?]

thanks everyone for your help I think I will start by spraying leaves all over including underside with round up then possibly later in the year cut them back and drip down the hollow stalks.

[AlBags]

Proble is it propogates under the ground with tuberous runners.
Hard to eradicate completely.

[Whoever]

Take it very seriously. This is a wicked weed that has the potential to take over gardens and undermine paving, patios and even the foundations of houses. I've read reports that some building societies will not even grant mortgages on properties which have Japanese knot weed growing in the gardens because of its potential to spread and undermine concrete paving and brickwork.
I'd start cutting it back now and keep hacking and treating it with everything under the sun until you've got it under control. It's almost impossible to eliminate completely so you'll just have to keep battling.

[boxtops]

Have a read here - if you Google there are a number of companies offering to get rid of it for you http://en.wikipedia.org/wiki/Japanese_knotweed