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RE: plant vs. weed

OK, I was going to stay out of this, but the cute descriptions have now led
to one a little more problematic for me. Unfortunately, even reputable
dealers sometimes deal in noxious weeds.

First, let me say that the common term 'weed' is an ambiguous one. It means
different things to different people. I consider most lawn grasses weeds,
while my neighbor doesn't understand why I like fireweed so much. The term
"noxious weed" however is a legal one, and carries with it everything
lawyers and beurocrats can dream up, including the fine print. There are
federally listed noxious weeds, weeds listed only in particular states, and
in some cases only for particular counties. How the plants get on those
lists is probably at the heart of the original question. I hope.

At any rate, weeds are plants, though not all plants are weeds. I suppose
algae can also become a weed, but that gets off on a tangent I don't really
want to follow. What makes a plant a weed is still being debated by
scientists, but botanists generally agree it boils down to the ability of an
exotic plant (ie, a species from a different region, not native to the area)
to not only persist but naturalize and form self-perpetuating colonies. So
the bearded iris that survives in the vacant lot long after the house is
gone is not really a weed, more a remnant. But the 'hogproof' rose hedge
that starts seeding itself all along the riverbanks is. It is designated a
'noxious' weed when its spread either becomes a threat to agriculture or is
obviously a threat to specific habitats. Purple loosestrife has been the
poster child for the latter, but there are as many examples of plants that
threaten ag on the noxious weed lists in most states. It is also worth
mentioning that the listing of a weed as noxious is almost as political as
the listing of endangered species. Kind of the opposite end of the spectrum.
Some plants that obviously do great harm to the habitats they invade are
difficult to include on the lists because of pressure from the landscaping
and nursery industries. Ivy is close to a million dollar cash crop in the
northwest, regardless of the fact that it is killing our forests by slow

Now back to the point I wanted to make. Reputable dealers often do deal in
noxious weeds, especially the more ornamental ones. Sometimes noxious weeds
are extremely popular, for precisely the same reasons they become aggressive
weeds. They are very good growers, and often have showy flowers or berries.
Purple loosestrife, before it was declared a national weed and banned from
transport across the country, could be had in nearly every mail order
catalog from the largest nurseries on down to small mom and pop
organizations, as the straight species or in a dozen or so popular
cultivars. Most of these nurseries were very well respected. It took years
of education before many of these nurseries voluntarily or not dropped the
plant from their lists. Every once in awhile someone tries to make a case
for a new 'sterile' cultivar, and the debate flares up again. 50 years ago,
Myriophyllum spicatum was one of the best pond and aquarium plants you could
buy. With both plants, their hardiness in the garden and pond was exactly
part of the problem- they were able to spread all too easily outside the
garden into the wider landscape, and successfully propagate themselves once
established. The extent to which they disturbed those habitats and pushed
native plants out in the process is the reason they were declared noxious.
Still, many noxious weeds are not under such tight restrictions and can be
sold in most states.

This ties into aquarium plants as more and more of the plants we discuss are
being found spreading in more or less natural waterways. If other plants in
the aquarium trade get to the point where they spread aggressively enough to
prove a threat to native plants and ecosystems, you can expect them to be
listed in some way on the noxious weed lists. This is a rapidly evolving
field of research right now. I suspect it is a greater problem in the US in
more southern states where the temperatures are more similar to that of our
tanks. But if you have been following comments from some of the Australian
members of the list, you probably already realize that other countries have
similar laws.

Brett Johnson
Green Man Gardens
bnbjohns at attbi_com


Date: Wed, 27 Mar 2002 00:07:22 -0600
From: "Mike Walsh" <wellwood at cookeville_com>
Subject: plant vs. weed

 distinguishes a plant from a weed ?"
 A plant is something you buy from a reputable dealer, while a weed is
 something you buy from a nut in Copiague New York.