Friday, September 13, 2019

Pulling Wild Carrots

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.

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