Guest post by Patricia Chan, an undergraduate freshman in 2014 Byrne seminar on weedy plants
What is a weed?
Generally, it’s an incredibly hardy and pervasive plant that we as
humans deem undesirable for our purposes.
Whether it’s a thorny bush in our yard, a vine stealing sun from our
crops, or the wildflowers in our lawns that “ruin” the uniformity of our grass—weeds
are what we make of them.
How to tell if that
plant is a weed:
·
People don’t like it
·
It’s hard to get rid of
Honestly, I could talk all day about how we define plants as
“bad”, “harmful”, and “ugly”, but enough about that. Let’s discuss the second aspect that makes a
plant a weed: their ability to survive, reproduce, and even flourish in the
most trying conditions. If you look at
it this way, weeds are pretty
incredible. They manage to succeed in
environments that limit all others and they seem pretty happy doing so too.
In terms of ultimate hardiness and survival, weeds are the
all-out winners. They have and they
continue to outwit other plants and animals every day, everywhere.
There are hundreds of adaptations that weeds evolve to
outcompete other plants and evade humans, but my favorite adaptations are their
aggressive defenses. The parts of a weed
that shout “I AM PREPARED” in the
face of adversity.
Some plants produce oils that target and irritate animals
trying to disrupt them- a commonly known one being poison ivy.
Some plants produce thorns- that’s normal. But then some plants produce serious
don’t-you-even-think-of-touching-me-thorns.
That’s the case in the honey
locust. While its thorn-less variety is
commonly grown around urban areas, its natural state is feared and frowned upon
by most. It has thorns covering the
entire tree, with thorns growing off of thorns growing off of thorns. No human or animal would ever want to mess with
that tree.
cc Greg Hume
above: honey locust thorns growing straight off the thorns growing off of the trunk
.http://upload.wikimedia.org/wikipedia/commons/thumb/3/32/HoneyLocustThorn.JPG/220px-HoneyLocustThorn.JPG
Some plants, like the black walnut, go so far as to emit
chemicals from their roots that kill plants around them and prevent others from
growing. Because of this, the black
walnut tree can enjoy its nutrients and sunlight uninterrupted by close
competition. It is also because of this
that the tree is considered a horrid weed by gardeners and farmers alike.
Acacia trees are yet another weedy and plentiful species
with clever survival strategies. In addition to their thorny defenses, they use
chemicals to communicate with each other when threatened . They are responsible for confusing countless scientists were studying unexplained antelope die-offs seemingly. It turns out that when
the antelope munched on the acacia leaves, the tree signaled to itself (and others) to begin
producing toxins to reduce the threat. That’s impressive.
Any way you put it, weeds are an amazing achievement. Most of us gardeners, farmers, homeowners, or
bystanders may not appreciate weeds on a surface level, but let’s now recognize
all the work in evolution that led them to where they are now. Sure, invasive, mass spreading weeds may not
always be conventionally beautiful, but there’s a reason why they’re hard to
get rid of: we selected them to be that way.
Next time you see that weed that seems to always come back,
take a moment to applaud it as an impressive feat of nature, because that’s
what weeds really are: they’re tough.
