On 09/08/2017 20:47, Chris Hogg wrote:
On Wed, 9 Aug 2017 10:23:36 -0700 (PDT),
wrote:

Well I am glad to have found this forum, although it confirms my worst suspicions.

Fact is I now have suckers popping up all over the lawn and towards the house (it's ranged about 15 ft from the original tree which last winter I cut back to a stump.... but that set it into survival mode and its voracious suckering commenced. I have a further smaller one (5ft) - which I appear to have succesfully seen off using a weed killer (on the leaves).

I shall be using the same method (weed killer) on the larger tree bark and leaves - and also spending a good week digging every single last root of this invasive. Will let folks know how long it takes to see off completely/progress on the eradication!

Repeated mowing should eventually make the suckers give up. You could
also try a stump-killer such as Root-Out (technically, ammonium
sulphamate) http://tinyurl.com/y8jwzht4 Drill a few deep holes into
the original Rhus stump and spoon in crystals of the stuff, and cover
with a tile or poly bag tied around with twine to keep the rain out.

+1

adding a trace of copper sulphate also speeds up the rotting process
(paradoxically by inhibiting anti fungal enzymes in the live wood)

Regular mowing and/or Verdone weeds in lawn treatment will see off the
suckers but there is a lot of stored energy in old tree roots and it may
well persist for a season or two before it expires completely.

--
Regards,
Martin Brown