[AlaninCarlisle]

I'm puzzled about the instructions for killing ivy with SBK brushwood killer. Basically it recommends mixing it with light oil and applying it to the ivy in the DORMANT season. This seems counter-intuitive as surely the leaves won't absorb it if the plant has ceased to grow. Am I missing something here?

[New shoot]

I think the theory is that when Ivy is actively growing, it can shrug off weed killer or regenerate from bits of roots.  if you treat it when it is not growing, the weedkiller has chance to kill it all.  You might have to be on standby for another application in spring if anything else emerges.

Me and my plot neighbours hatched a plan to do a similar treatment on an empty plot bordering our plots last autumn.  It killed a big grape vine we had cut down, that was threatening to take over the world, plus shrubs and ivy.  Although it hasn't killed the brambles outright, it certainly knocked them right back.  I've been spraying them with glyphosate since if I spot them.

[Auntiemogs]

From what I managed to find, it's because when it's going dormant it starts to take in and store nutrients, and will do the same with the weed killer too.

[wighty]

I've just double checked with Paul as he sells it in the shop and I had remembered right, you can mix SBK with paraffin to use on tree stumps, ivy and other 'thick skinned' weeds.