On Sat, 25 Aug 2012 09:13:02 +1000, F Murtz
wrote:

David Hare-Scott wrote:
Brooklyn1 wrote:
"David E. Ross" wrote:

If you really want to kill the ivy, apply Roundup to the foliage
with a sponge or brush, which will avoid damaging the tree on which
it is growing.

That's much too risky. The ivy will quickly draw the Roundup deep
into it's roots where it will be deposited in close proximity to the
tree roots, whereby it will severely damage if not kill the tree.

How do you know this? When a plant is growing strongly roundup is drawn
down into the plant after it is applied to from the leaves, this is
docmentated as part of the way it works and the reason using it on
dormant plants is largely a waste of time . Where did you get the bit
about it crossing from the ivy roots to the tree roots via the soil?

David


Does the ivy use the tree sap when it attaches itself so tenaciously to
the tree ? IE. is it parasitic ?

Yes, it's parasitic, but it doesn't suck the sap per se, it extracts
nutrients from the cambium the same way ivies extract minerals from
masonary, slowly weakening the tree making it susceptible to diseases,
and eventually killing it.