Driving around Miami Valley highways it’s easy to spot a plant that appears to be wild carrot; however, not all of these plants that look identical to wild carrot are actually wild carrot.
Poison hemlock is sometimes mistaken for wild carrot; however, it’s quite toxic in comparison and is one of the most toxic weeds in North America.
Both plants are members of the carrot family, which contain many edible plants including carrots, parsnips and celery as well as herbs such as cilantro, chervil, anise, parsley, fennel and dill.
Both are biennials, which means they grow vegetatively the first year and flower and go to seed the second. Those in flower now will produce seeds to keep the species alive for years to come.
Both plants are usually found in fields, pastures, vegetable crops, roadsides and other disturbed areas of land. Right now, they are both in full bloom with white flowers on top of plans that are around 4 feet tall.
At this time of the year, you can see both of these plants along the highway very easily, as they are in full bloom.
Wild carrot is not toxic; poison hemlock is. It contains highly toxic piperidine alkaloid compounds that can cause respiratory failure and death when ingested by mammals.
Animals tend to stay away from poison hemlock unless other forage is not available. It’s still a good idea to check for it.
It’s important for you to be able to distinguish between these two plants, especially if you are trying to eradicate them. Both have hollow bluish-green stems, and the plants almost look identical. However, poison hemlock has distinguishing purple blotches up and down the stem. It’s easy to tell them apart.
Control can be achieved by tilling or mowing. Now is the time to mow it down before it goes to seed. If you are going to use a weedeater to cut it down, make sure none of the juices from the plant get on your skin.
Poison hemlock can also be controlled by both selective and nonselective (kills everything) herbicides.
One of the alkaloids in poison hemlock, coniine, is a neurotoxin and can be absorbed through the skin, therefore wear long pants and long sleeves as well as glove if removing these plants.
You might think that this plant won’t bother the gardener because of where it’s normally located. It’s true as this is not usually considered a landscape and garden problem. However, I am seeing more and more of it in home gardens. I now have it creeping into my garden and perennial beds and have been diligently working to eliminate it.