If
you're new to the world of native plants, and nobody in recent
generations of your family has been a farmer, you might not
know about Johnson Grass. In fact, you might even drive by fields
of it on your way to work every day and think to yourself, "That's
a nice little patch of prairie." Because it grows tall
and blows in the wind just like the movie images of prairie,
it's easy for the average layperson to be deceived from a distance.
But ask any knowledgeable farmer about the difference, and they
will set you straight.
This tall
and graceful-looking grass was first brought over from the Mediterranean
as a gift to a plantation owner in Mississippi just 150 years
ago. He liked it, and established it on his land where it grew
thick and fast. From there, it has spread all over the southeastern
quadrant of the United States and can be found in spots as far
west as Texas and even California. It thrives on any patch of
disturbed soil it can find, whether plowed or bulldozed or just
overgrazed and overworked. A single plant produces up to 5,000
seeds per year, and those seeds can lie dormant in the ground
for up to twenty years to come.
Johnson
Grass particularly loves fields plowed up for agriculture, of
course, and it has literally destroyed millions of acres and
bankrupted thousands of family farmers in its march across the
land. Suffolk County in West Virginia has made it against the
law to have even a single Johnson Grass plant on your land because
it is so destructive to farmland. But unbelievably, some seed
dealers still sell Johnson Grass seeds!
No doubt
that plantation owner in Mississippi had no idea what he was
about to unleash on the continent when he accepted the gift
of Mediterranean grass from his friend. He just wanted to establish
a nice hay field to feed his cattle and horses, and this plant
seemed to fit the bill. But he and others were soon to find
out that during times of drought and under stress, Johnson Grass
produces an acid that is poisonous to those same cattle and
horses. And we can imagine that the first time that happened,
they might have decided to mow the stuff down and plow it under
to get rid of it. But they were in for a big surprise.
 |
Mister Johnson's
Curse spreads rapidly and aggressively by rhizomes as well as
by its prodigious capacity to produce seeds. Unlike prairie
grasses, its roots are shallow, so it does nothing to aerate
the soil or to draw water deep into the ground. It also exudes
a natural toxin from its root system that prevents other plants
from growing close to it, so effectively serves as a "herbicide"
to the competition.
We've heard
that persistent severe grazing will eventually kill it off,
but that can take years. Removing it by hand is an arduous process,
because every part of the tough and extensive rhizomes must
be located and pulled out of the soil or it will just spring
back again.
So what
should you do if you have Johnson Grass on your land? Solarization
removal methods can be effective (see our Native
Grass Planting Tips page) if it exists in smaller colonies
and hasn't spread too far. For larger areas, we have used repeated
plowing over the winter months to expose the roots to freezing
temperatures and dry them out during sunny and dry spells. On
native prairie restoration projects, we have made an exception
to our general rule of avoiding chemicals, and carefully applied
herbicide directly to the plants.
If nothing
else, Johnson Grass should always be mowed to prevent it from
blooming and going to seed, while you work persistently and
patiently to remove it from your land.
|