Farm1 wrote:
"David Hare-Scott" wrote in message
...
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?

Have you ever used Roundup near roses? It has a very detrimental
effect on roses and it's not as a result of spray drift. I have to
say that I tend towards agreeing with Sheldon on the soil effect.

I have to say to start I don't know the answer and I am asking questions to
try to work one out. The reason I doubt the crossover from root to root
idea is that glyphosate is said to be quickly deactivated in contact with
the soil so it seems a bit much for it to cross two membranes and the soil
and arrive intact. The idea that ivy draws on the fluids from its host
seems a more promising mechanism to me. If anybody has any references to
that I would like to read them.

D