In article , "Ralf G. Toennies"
wrote:
If there still is a stump, drive copper nails in it. That may stop the new
shoots.
I have often seen it repeated that unwanted trees can be killed by driving
copper nails into a tree, & stumps can be stopped from suckering. One
method is to completely ring the bottom of a tree with 10d copper nails at
one-inch intervals, then wait two years. I've never seen any actual study
that proved this would work; if it did seem to work, I suspect it would be
because of the damage done to the bark; removing the bark from around the
base of a tree would be vastly more certain way to kill the poor tree.
Copper at high enough levels certainly is toxic to plants, & can suppress,
for example, algae growth in a pond. At extremely low levels however it is
not harmful, & copper as a solid is so slow extremely slow to decay that
copper was traditionally used in roofing & boat manufacture as one of the
most stable metals. I do not know for certain, but I do not believe a
toxic level of copper can leached out of copper nails.
If it could, then so too would copper trellises & copper watering pots &
copper flower pots kill stuff, & water running off roofs with copper trim
would be toxified. I'm aware of no evidence that this is true. Here is a
typical line of garden products made of copper:
http://www.gardenartisans.com/arbor.html
If they were ground up into filings & mixed into the garden they would be
harmful, but nothing short of that I'd reckon.
To kill whatever life is left in a stump, drilling a few holes &
filling them with copper sulfate might indeed kill whatever life is left
in it. Copper sulfate is available from a plumber supply. I'd do some
more research before I tried it though. By right of killing funguses,
copper might SLOW DOWN the decay of a stump, which will otherwise be
broken down over time by funguses.
The copper nail thing might be credible, but I'd have to see some data to
believe it. It seems that just about everyone has HEARD it works, but
almost nobody knows where to get copper nails, so I suspect it's just one
of those perpetually repeated rumors that no one has actually tested. When
I made a quick-search for any study or proof, I could find nothing
definitive, though the International Society of Arboriculture says it is a
myth, that if there were any truth to it, fungicides which deliver vastly
greater amounts of copper to a plant or tree would kill it
http://www.wcisa.net/myths.asp.
Another non-study which nevertheless makes a lot of sense is on-line at
Garden World, a footnote to an article on building stuff with copper for
the garden:
"It is a commonly held misconception or 'old wives tale' that copper nails
kill trees. Copper in its metallic form is not toxic to trees. The only
damage that may have occurred is simply mechanical. Thus, if there are
enough nails around the circumference of a tree to completely girdle it,
then it will die, but otherwise there will be little damage other than a
potential point of entry to decay fungi."
http://www.gardenworld.co.uk/project-copper.asp
A real field study would be more valuable, of course, but I strongly
suspect the assessment of this notion as an "old wives tale" is the
correct assessment.
-paghat the ratgirl
--
"Of what are you afraid, my child?" inquired the kindly teacher.
"Oh, sir! The flowers, they are wild," replied the timid creature.
-from Peter Newell's "Wild Flowers"
Visit the Garden of Paghat the Ratgirl:
http://www.paghat.com