As the seasons change, my management activities change. Summer is a time to hunt and eliminate
invasive forbs and grasses. Sweet Clover
was my initial target several years ago.
As Sweet Clover numbers dropped, I added other species that could be
controlled by pulling prior to setting seed.
Now, Yellow and White Sweet Clover, Wild Carrot, Teasel, and Oxeye Daisy
are all on my summer pulling schedule.
Not all invasive species can be controlled by pulling. Sometimes, like in the case of Crown Vetch,
the aid of a chemical herbicide is necessary to eliminate the plant.
This is my second year using the chemical Clopyralid in the
treatment of Crown Vetch. Clopyralid
kills only broadleaf plants, and is particularly effective on legumes. Grass is left unharmed, so no bare spots are
left in the field after treatment. The
areas I treated this year were fewer in number and much smaller than what I
dealt with last year. Shown above is the
largest patch of Crown Vetch I had to spray this year, and it covered only
about 40 square feet.
Crown Vetch found its way into my fields as seed that was produced
along the edges our township road. I
eliminated the roadside vetch last year, but some of the affected field areas
are going to take a bit more work. Crown
Vetch growing beneath the canopy of tall Indian Grass is hard to spot. The best time to search is when the plants
begin to flower.
Unfortunately, peak flowering time for Crown Vetch coincides
with flowering of other lavender bloomed plants such as Monarda. Shown above is Crown Vetch on the left and
Monarda on the right. Colors are almost
identical.
Monarda flowers are held above the Indian Grass leaves. Good luck trying to spot a couple stalks of
Crown Vetch hidden down in the grass.
Johnson Grass is another species that requires some
herbicide assistance if it is to be eliminated.
I’ve been after this species for several years and only found seven
small clumps growing this year.
When dealing with Johnson Grass, I first cut the stalks down
to a manageable height and trim back any long, flowing leaves. This allows me to spray the complete plant
with glyphosate, without spraying a lot of neighboring plants.
Johnson Grass is another invasive species that can trace its
origin back to the roadside. Even though
the roadside along my property is free of this invasive grass, seed produced
along other sections of the road are easily caught and transported by vehicles
traveling the roadway. I expect
passersby will replenish my seed supply on an annual basis.
Johnson Grass is hard to miss when it sends up a flower
stalk. This species puts on height in
late July, long before the tall prairie grasses, so it doesn’t take much
searching to identify new infestations.
When the plant is blooming, tops can be cut and just left in
the field. There is no chance that these
flowers will produce viable seed if removed from the plant at this stage. If treatment is done after seed has formed,
it is best to remove the seed heads from the field to eliminate any viable seed
being left behind.
I began pulling Wild Carrot six years ago. I’ve had a lot of success in reducing the
numbers of this plant.
Areas that once yielded hundreds of plants, are now
producing only a few plants each year.
With fewer plants to pull, I can cover more area. This is the last of the Wild Carrot infested
barrens, an area that I have never had time to get to before. I was able to finish off this field just as
the pulling season came to a close.
Wild Carrot seeds were just beginning to darken during my
last week of pulling. Not knowing if
these seeds were developed enough to finish ripening on a pulled plant, I removed
the seed heads and bagged them for disposal somewhere other than the middle of
my field.
A single Black Swallowtail caterpillar was found on one of
the pulled carrots. I transplanted it to
a domesticated carrot variety in my vegetable garden. It ate for several days and then
disappeared. I hope it went off to find
a secure place to pupate.
