"Bob S." wrote in message
oups.com...

Blue wrote:


Depends on the type trees. I use it quite a lot and have found that
cedars don't like it at all. Sweet gum may show some leaf browning
if
spray gets on any suckers. However, most hardwood trees tolerate it
quite well.

Bob S.

I experimented injecting it into drilled holes in the roots of a
bottle
brush I wanted to get rid of. IN three years it had zero effect on
the
plant.

Roundup is not a universal plant killer - some plants are just not
affected by it.
The cambium layer in a plant carries nutrients & water back & forth
within the plant. This layer is between the bark and the wood. If the
bark is dense and tough, it protects the cambium layer from roundup. If
the bark is soft, like cedar, roundup can be absorbed through the bark
much like through leafs.
In your case, instead of drilled holes you may have done better to peal
the root bark and apply full strength roundup to the pealed area. But
then bottle brush may be one of those plants that roundup doesn't
affect.

Bob S.
Somebody once told me that a "copper nail" put into a tree trunk would kill
the tree. Any truth to this?