Re: Invasive Plants

**Conrad Richter conrad@richters.com>**

> Date: Thu, 20 Jun 2002 
> From: Carol Hughes <cahughes@sentex.net>

> Euonymus alatus (escaped from cultivation in the eastern U.S.) and
> Buddleia davidii (escaped from cultivation along the eastern seaboard
> from Pennsylvania to North Carolina, and along the west coast in
> California, Oregon and Washington. 

Perhaps we should distinguish between invasives that escape but cause no
appreciable harm and those that do.  There are countless naturalized
species in every region that do little or no harm.  Yarrow (Achillea
millefolium) and wild carrot (Daucus carota) are just two that are
common in my area (southern Ontario): both have been naturalized here
for a long time, probably for centuries.  Neither of these plants is
considered to be noxious to farmers or others in any way.  It seems to
me that to condemn a plant just because it escapes is simpleminded.  I
don't mean to suggest that the two species mentioned by Carol are not
problems; they could very well be.  I honestly don't know about those
two because I have not seen them in the wild.  But I think it would be
helpful to everyone to narrow the debate on invasives to only those that
are known to be problems. 

Also, at the core of the debate is the assumption that species diversity
in the wild ought to be static.  Well, species diversity is almost never
static.  Succession -- an ecological term referring to the natural
progression of species invasion and exclusion over relatively short
periods -- is quite the norm in healthy ecosystems. (Succession, by the
way, is NOT the same as the natural speciation that occurs over much
longer evolutionary time.)  Now, if the argument against escapes --
whether they are "problems" or not -- is merely that escapes alter the
natural species diversity and that's bad, then maybe we gardeners all
have a problem.  Heck, even tomatoes can reseed themselves in my
zone 5 garden.

My big worry is that the dividing line between "good" and "bad" is going
to be put simplemindedly at whether or not a plant can reseed itself or
otherwise spread vegetatively.  Why do I think that might happen? 
Because who has the resources to put the dividing line anywhere else? 
To decide whether a plant with the ability to escape is actually going
to become a problem (vs. those that won't) is a daunting exercise. 

Conrad Richter

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