In message , Tam
Inglis writes
Hi,

I've spent the last week digging and sifting the rhizome system of an
infestation of Japanese knotweed.

however I've now come up against the fact that it is running underneath
the driveway/patio.

I thought i had caught it before it would have spread there (and indeed
it is relatively clear) however there was one 'crown' perhaps a meter
at the closest point to the patio and as a result there two main roots
heading off directly underneath the driveway and patio.

I'll take the bricks and patio slabs up if nothing else presents itself
but if anyone has any help/tips for removing/killing a root system
underneath non-diggable area it would be *greatly* appreciated.

T
Wait for it to shoot then inject neat glyphosate into the stems, Spring
or Autumn.
--
bert