Jobs such as mowing or the cutting and dragging of brush are performed during the fall and winter, when the plants are in decline or already dormant. There are some jobs however, that must be done in the middle of the growing season. One of those is the removal of Sweet Clover from the fields.
This prairie opening was once the site of a
healthy infestation of Sweet Clover.
Annual removal of the invasive species prior to seed development has
resulted in a site that is almost clover free.
Yellow is the earlier
bloomer, but White is not far behind.
The most effective method I have found of dealing with this plant is to
physically pull it from the ground.
Clover pulling season begins around the last week of June and continues
into late July. I search through the
open field areas and remove every Sweet Clover plant I can find. This has been an annual activity for several
years and in most locations the clover is present only as widely scattered
individual stalks. It’s fairly easy to
move around the field and deal with the clover without trampling too much of
the surrounding vegetation. During my
first few years of this activity, the clover was so abundant my trampling gave
the appearance that a herd of cattle had run through the field.
Queen Anne’s Lace is
another biennial that can be effectively controlled by annual plant
removal. Some people prefer the name
Wild Carrot, but I think that name makes it sound like the plant somehow
belongs here. I prefer a name that
reminds of its exotic origin. Now that
the Sweet Clover is so reduced in number, I can give more time to removing the
Queen Anne’s Lace. I also pull Oxeye
Daisy from the more established prairie areas.
Older Oxeye Daisy plants, those that have begun to send out rhizomes,
cannot be pulled without leaving growing bits behind. During its first year of growth, the plant is
composed of a single stalk and its associated root system and can be removed in
its entirety. Hopefully I’ll be able to
stop Oxeye Daisy from moving into new territory.
There’s always a chance
that some of the plants have been able to develop viable seeds prior to being
pulled, so I don’t leave any pulled plants in the field. If there are seeds in the bunch, they will
fall down through the brush pile and have a very poor chance of ever producing
a mature plant.
Vetch is a notorious invasive plant that was once commonly planted on steep
road banks. The road bordering Blue Jay
Barrens was so treated in the late 1970’s and I am constantly dealing with
Crown Vetch flair-ups in the fields near the road. The really disturbing part about finding
Crown Vetch in this location is the fact that this opening is far from the road
and in a watershed that does not come close to the road. When an invader comes from an identifiable
source and travels a particular route, such as down hill or down stream, you
can anticipate where it is likely to occur and plan for those events. An incursion this far outside the predicted
pattern makes me fear that Crown Vetch could be a threat to any part of the
The stem has a weak point at
ground level that allows it to break away rather pull up the roots. The roots are left in place to grow a new
plant. This is a common feature of many
plant species and allows them to survive in areas that receive heavy grazing
pressure. If this infestation was in an
old crop field, I would just spray it with glyphosate. Being in an area that I consider a higher
quality prairie, I didn’t want any collateral plant damage. I chose to clip the Crown Vetch stalks about
an inch above the ground and apply concentrated glyphosate directly to the
stump. This is a more tedious process, but the result is the death of the vetch
and an unblemished prairie.
There is a point where the quantity of Sweet
Clover makes hand removal impractical.
If this little corner was the extent of my management area, I could
certainly wade in and pull each one of those thousands of clover plants. This calls for a different management strategy. In order to reduce the number of clover
plants, the plants must be denied the opportunity to produce seed. An alternative to pulling the entire plant is
the removal of the flower. I
accomplished that task on June 16 by mowing this part of the field.
far, the clover has failed to return.
The native plants, primarily Indian Grass, are regrowing nicely. Hopefully, mowing will bring the number of
Sweet Clover plants down to a more manageable level.
handsome caterpillar was busy munching away on one of the Yellow Sweet Clover
plants. I identified it as the larva of
the Hitched Arches moth. It appears that
this moth eats a wide range of plant species and is not a super Sweet Clover
predator. It may not help me with my
task, but it was nice to share the field with this small helper.
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