Several articles have shown up recently about poison hemlock. It does grow here in the Ozarks and this is my poison hemlock eradication method.
There was a stretch of this plant along the road by the barn. It was a hundred feet long and several feet wide when I began getting rid of it.

I don’t use herbicides normally and didn’t want to for this. A row of asparagus was behind part of this stretch. Elderberry and day lily were growing there too.
Poison hemlock is considered the second most toxic plant in Missouri (Number one is the invasive water hemlock.). It can grow as an annual to a short lived perennial, but is mostly a biennial. That means it has a rosette of leaves one year and blooms, then dies the next year.

My poison hemlock eradication method made use of this life cycle. When the plants put up their flower stalk, I cut them down. The plant died.
There is a drawback to this. Once the flowers open and are pollinated, they will set seed. Any surviving seed means more plants.

I stuffed the flower stalks in empty feed sacks and let them dry. Where I live I can burn my trash in a burning barrel and, once the plants were thoroughly dry, I burned them.
The first year was the worst in terms of the number of plants to cut down. The second year was not much better. By the third year there was a definite drop in the number of plants.
My poison hemlock eradication method does take dedication. Gloves are a good idea, although I rarely use them. Keep the sap off your hands, etc. and wash up right afterwards. The poison danger is from ingesting (eating) the plant or its sap.

This year I found a few plants trying to grow near the asparagus row. They were easily dug up and disposed of. Three bloomed and were similarly dealt with.
It was a lot of work, but I consider my poison hemlock eradication method a success.
I have plant pages posted several years ago on water hemlock. It has a general plant description with pictures.