The flower head of the Wild Carrot, Daucus carota, is made
up of myriad small individual flowers, each capable of yielding a single seed.
Since each plant is capable of producing multiple flower heads, a single plant
may produce hundreds or even thousands of viable seeds. This may be a lovely
proposition for those wishing to expand their population of Wild Carrots, but
it can be a headache for people trying to manage areas as native ecosystems. My
management efforts aim towards creating conditions that favor the growth and
spread of native species. While Wild Carrot may be attractive and a favorite of
many people, it is not native to North America and can act to degrade areas
into which it invades. In order to protect and improve the native integrity of Blue
Jay Barrens, I remove non-native species from the property and that includes
ridding the fields of Wild Carrot.
The Wild Carrot is not the only invasive species I work to
eradicate during the summer months. Sweet Clover, Teasel and Oxeye Daisy are
also on my list of invasive plants to be pulled during the summer months, but
they mature at different times through the summer, so multiple visits must be
made to each management site during the year.
The photo above shows a collection of plants pulled from a small Prairie
area during the first week of June. Plants on the left are Sweet Clover, those
in the middle are Oxeye Daisy, and the small pile on the right side is Wild
Carrot. Wild Carrot is just becoming noticeable in June as its developing
flower stalk begins to elongate.
By the time August 1st arrives, Wild Carrot plants
are a few feet tall and supporting a nice collection of white flowers. All
pulled plants are gathered up and placed on an existing brush pile. It wouldn’t
hurt anything to leave the plants in place to rot down naturally on the prairie,
but doing that makes it difficult to see all of the plants that have not yet
been pulled. I don’t want to risk
leaving plants in place that are going to produce seed for future generations.
Besides, I enjoy finishing work on a site and then immediately viewing the area
in its improved condition.
I always carry a camera with me while I’m working and try to
get a few before and after shots. Often the camera doesn’t come out of its
holster because I’m racing to finish an area before I run out of time, or I’m
sweating so profusely that I’m afraid I’ll ruin the camera if I try to use it.
I did make a special effort to take this shot on a fine August morning when the
temperature reached 90° F by 10 AM. This is a small section of a 1 acre opening
that had never before received any carrot pulling treatment. My success in eliminating
invasive summer forbs means that each year I have time to add new areas into my
work schedule.
This is the same area with carrots removed. Within a few
years the area should pretty much look this way without my having to spend
hours pulling carrots.
Wide area shots of these prairie openings rarely show the
diversity of plant species present. Spiranthes orchids, such as this pair of
Slender Ladies’ Tresses, Spiranthes lacera, were particularly abundant this
year. They are but one of many interesting
little species hidden in the tall grass.
Pulling is an effective way of eliminating Wild Carrots
because of the plant’s biennial growth habit. The lifespan of the plant is two
years. During the first year the plant forms a cluster of basal leaves and
establishes its taproot. The abundance of first year plants such as the one
shown above gives a good idea of the expanse of plants to be expected in the
next year.
A flower stalk develops in the second year. Following
pollination, seeds begin to develop as the flower head closes in on itself.
Pulling the plants eliminates seed production and reduces the number of
flowering plants you will see two years later. Mature seeds that become
incorporated into the soil may remain viable for five or six years. Seeds that
remain on or near the surface of the soil generally parish if they do not
germinate within a couple years. When you begin pulling plants on a new site it
takes two years before you really begin to see the positive results of your
actions.
Like many plant species that evolved in areas subject to
grazing by herd animals, the Wild Carrot has a weak spot in its stem located
roughly at the soil surface. If the stem is given a quick pull it breaks at
this weak point instead of having its root pulled out of the ground. Just below
this breakpoint is a cluster of buds ready to immediately begin producing new
flower stalks if the top of the plant is lost. On most occasions, a steady pull will bring the plant up root and all. When you have a particularly tenacious plant or are working in ground
that is extremely dry and hard, the carrot often breaks at its weak point. When
this happens, I normally use my hand pruners to cut the plant off down into the
root slightly below the ground level to avoid the rapid regrowth shown in the
photo above.
Often it’s impossible to find the plant stump and regrowth
is inevitable. This plant produced two flower heads within four weeks of the
plant originally being pulled and broken off at its weak point. I try to make a run through my work areas at 4
to 5 week intervals to catch late developing plants or regrowth situations such
as shown here.
Browsing animals, primarily Whitetail Deer, typically bite
the plant off well above the soil surface. Browsed plants are particularly
difficult to see when you make your first pass through an area, but quickly
produce new flower stalks and often account for the majority of late-season
flowers.
I found many mature plants that were lying flat on the
ground instead of standing in an upright position, making them particularly
hard to see. This was primarily a phenomenon of partially shaded areas near the
field edges. In the above photo you can see two flower clusters almost at
ground-level. One plant stem comes from
the lower right-hand corner the photo and arcs leftward to one of the flower
heads and a second plant stem comes from the lower left-hand corner of the
photo in a rightward arc to a second flower head. Despite their horizontal
growth, both plants are still perfectly capable of producing viable seeds.
This particular area has received a lot of attention in the
past few years. A mid-July photo shows no Sweet Clover, no Teasel, and no Wild Carrot.
It shouldn’t be too many more years before all the areas have reached this
level of control.
I always find a lot of interesting things while I am working
and try to stop occasionally to take a few photos. One day I found a number of Poison
Ivy Sawflies, Arge humeralis, feeding on the carrot flowers. They were
impossible to miss with the sun shining off those bright red abdomens. I’m much
more used to seeing the sawfly larvae, so I was pleased to get the opportunity
to observe the adults.
The following day, I continued to see adult sawflies, but
now I was seeing a different species. On this day it was the Sumac Sawfly, Arge
coccinea, that seemed to have staked a claim to the local wild carrot flowers.
Every year I see a couple of Black Swallowtail butterfly
larvae feeding on the wild carrots. I took this one and moved it onto a cluster
of nearby first year basal leaves. If
they want to continue breeding at Blue Jay Barrens, they will have to select
one of their few native host plants.
