Lurking along some roadsides, irrigation ditches and fence rows in Jackson County are some potentially lethal weeds disguised as attractive white flowers with purple-spotted stems and shiny leaves.
Poison hemlock is a toxic plant and can be lethal if ingested. The biennial weed often is mistaken for wild carrot, also known as Queen Anne’s lace, or wild cow parsnip.
“It is a biennial, which means the first year, it’s just a small growth of green leaves with no flowers,” said Richard Beckort, director and educator with Purdue Extension Jackson County. “The next year, there is a large bloom stock, which could reach 6 or 8 feet tall.”
When the hemlock grows to such heights, that is when it is most noticeable. This happens in late spring and early summer. It is out there now and already has bloomed and started to turn brown, Beckort said.
“It’s probably been in the last five years or so that it’s been showing up,” he said. “After a couple of dry years where other things die out, it tends to get a foothold and take over.”
The hemlock is a real danger to livestock and wildlife, especially if it is around pastures or hay fields. If it’s in a hay field and gets baled up with the hay, there’s a chance the livestock could eat it, bundled up with other forage, Beckort said.
A single poison hemlock plant can produce more than 30,000 seeds, which can potentially stick to farm machinery, vehicles, fur and clothing. Even after the hemlock dies, the cane of the plant can remain toxic for up to three years.
Eating the plant is the main danger, but it also is toxic to the skin and respiratory system. People can have reactions when pulling the poisonous plants due to toxins absorbed into the skin.
Beckort suggests taking extra precautions when cutting and mowing areas where the hemlock is present.
“Wear a mask to avoid inhaling the toxin,” he said. “Gloves and other protective gear can help prevent the poison from getting absorbed into the human system.”
The hemlock releases a foul parsnip-like odor when its leaves are crushed. If the weed is in a place where livestock are, they tend to pick around it because it’s not very palatable, Beckort said.
Early spring growth, however, is the time when hemlock is more likely to be eaten by animals because there is limited forage available, said Jeff Fisher, executive director for Jackson County Farm Service Agency.
“It was in Lawrence County prior to here but has been here for several years now,” he said. “Anyone that bales hay should learn to identify this plant.”
Most cattle farmers Fisher has spoken with are not familiar with the plant yet. It appears to pose a bigger problem with hay than in pastures, he said.
“Lawrence County has been dealing with it for several years where they have a lot more cattle farmers,” Fisher said. “Cattle will not eat it if given a choice of other food in a pasture, but in the winter, they do not have as much to choose from.”
If a cow or other animal ingested poison hemlock, it would depend on how much they ate and what percentage of the food they ingested, but it doesn’t take a whole lot to cause some issues with livestock.
Dr. Kristin Tormoehlen, veterinarian at Brownstown Veterinary Clinic, said she does not know of any local farmers with animals that have been affected by consumption of poison hemlock.
“I have never treated an animal affected by its consumption,” she said. “All portions of the plant are poisonous. This includes the stems, leaves, root and mature fruit. The leaves are most dangerous in the spring, and the fruit is the most dangerous in the fall.”
Symptoms include nervousness, trembling, muscle weakness, incoordination, salivation, initial stimulation or excitement followed by depression, dilation of the pupils, weak heartbeat, musty, mousy odor to breath and also in the urine, Tormoehlen said.
“There could also be prolapse of the third eyelid across the cornea, which may cause temporary blindness and death by respiratory failure due to paralysis of respiratory muscles,” Tormoehlen said. “If subacute intoxication occurs during pregnancy, it can lead to deformations in the fetus, including cleft palates and deformed joints.”
Treatment generally is cost-prohibitive in livestock, and most animals die before it is found that they have consumed the plant.
If treatment, however, would be attempted, respiratory stimulants and gastrointestinal protectants could be used along with supportive care, said Tormoehlen, who is a member of the Jackson County Board of Public Health.
“The best time to get rid of it is during the first year of growth,” Beckort said. “Most broad-leaf weed herbicides like Banvel, Dicamba and 2,4-D can help control it when it’s small, but after it blooms, it’s very difficult to control.”
To battle this invasive toxic plant, education appears to be the key to eradication. Anyone who would like information about poison hemlock may contact Beckort at the extension office in Brownstown.
“We can talk them through the poison weed and the control of it,” Beckort said. “Poison hemlock has been pretty rampant throughout the county this summer. Once you see it, you notice it everywhere.”
[sc:pullout-title pullout-title=”Socrates died from poison hemlock ” ][sc:pullout-text-begin]
Socrates was a Greek philosopher credited as one of the founders of Western philosophy. In 399 BC, when the political climate of Greece turned, Socrates was sentenced to death by drinking a mixture containing poison hemlock, which paralyzes the nervous system. He accepted this judgment rather than fleeing into exile.