On Sat, 23 Oct 2010 22:15:45 +0100, Janet Tweedy
wrote:

In article , Martin Brown
writes
Why buy it now? The weather is already too cold for it to have a full
effect - applied at this time of year is a waste


Many of the more stubborn weeds inc. Japanese Knotweed are considered to
be more likely to be affected by poison if sprayed as they are winding
down for the year as they take the stuff into the roots.

But in September, not now. Now is surely too late.

Pam in Bristol