The beauty of wildflowers! Or are these weeds? To most people,
the picture above is one of richness and beauty. An ecologist
would agree. Yet the ecologist would see, technically speaking,
white flowers with the yellow centers are ox-eye daisies
garden escapes from Europe that are among our commonest
wildflowers. The yellow is moth mullein, and the brown-topped
grass is meadow fescue. All three of these are alien weeds.
define weeds somewhat differently than gardeners do. To
the ecologist, a weed is a plant that heals disturbances.
Something destroyed the original nature of the ecosystem
here. Maybe a bulldozer, or a plow. There is healing in
progress here. Beautiful healing.
weeds are wonderful plants. Some are native and some are
alien. We hear a lot of talk these days about alien invasives.
We'll get to them below. But most aliens are a valuable
part of local ecosystems. An alien red clover can supply
delicious nectar to the rare Aphrodite butterfly. More importantly,
a turf of simple weeds native or alien is
like a healthy scab that begins the healing of a wound.
Weeds in nature go away gradually, once the disruption of
the ecosystem has stopped.
the bottom right in the top photo, you may be able to pick
out the leaves of a dandelion. These leaves have the recurved
"lions teeth" that gave the plant its name (the
"dande" is from dens/dental meaning teeth). As
in your yard, if you stopped mowing and left nature alone,
the dandelions would go away in time. They thrive on mowing
or trampling but cant compete in a rich prairie or
the recovering area shown here were in a prairie preserve,
these weeds would be part of the healing process that would
tend eventually toward complete recolonization by the ancient
plants that the bison and elk ate. (The leaves of arrowhead,
visible in the water, show that some of those ancient native
plants are reasserting themselves already.) If this were
part of a well-managed forest, the ecosystem that would
win out would feature trees. Classic weeds can be a healing
step toward either forest or prairie.
disaster lurks. Notice the blue and pink flower. It's crown
vetch, an invasive. Invasive plants and animals, whether
native or alien, are one of the major threats to healthy
nature. To be sure, crown vetch may seem to behave like
a weed after an ecosystem is damaged. But it doesn't yield
to the diversity that makes for healthy ecosystems; in fact
it invades and degrades healthy ecosystems.
vetch can spread across prairie and eliminate most of the
richness of life there. Invasives in both prairie and forest
include native trees and shrubs. Its not the alienness
or nativity that makes the difference. It's whether the
species is one of the "out of balance" or "aggressive"
invasives that crowd out biodiversity and degrade the natural
managers are learning to control invasives in field and
forest. With invasives in check, we can once again appreciate
the beauty of simple weeds.
by Stephen Packard. Weed photo by Walt Anderson/Root Resources.
Butterfly photo by Jan Kanter.