Alan Bright, a fishing fly-shop owner from Spruce Creek, Pennsylvania, noticed a strange looking plant in his backyard in early June.

He didn’t know what it was, but curiosity about the 6-foot tall plant with it’s clusters of white blooms prompted him to contact the Penn State Extension Service, only to find out that he was looking at a very poisonous plant that also looked pretty, called poison hemlock.

Penn State Extension educator Sandy Feather said that poison hemlock is growing rapidly throughout Pennsylvania posing a dire threat to humans, livestock and other mammals that may touch and even more so, ingest or inhale it.

Feather goes on to say, “Breaking the leaf and getting sap on your skin will cause a rash, but the roots and seeds are super toxic. If you ate these parts you would get very sick.”

The US Department of Agriculture said the culprits in poison hemlock include contine, a chemical compound that disrupts the nervous system. Consuming the plant can cause trembling, lack of muscle control and coordination, rapid and weak pulse, respiratory paralysis, convulsions, coma, and death.

People who have eaten posion hemlock may have mistaken the root for wild parsnips, the leaves for parsley, or the seeds for anise, according to the US Department of Agriculture.

Sandy Feather went on to say that aerosolized particles also can trigger a severe, life-threatening reaction, so you do not want to weed whack poison hemlock. The plant is not native to Pennsylvania or any other part of North America. It was brought over from Europe in the 1800s as a garden plant prized for the tiny white flowers it produces in umbrella shaped clusters.

It grows six to ten feet tall, blooms from mid June through the end of August, and emits a musty odor. Two of poison hemlock’s more distinguishing features are purple spots on its stem, and lacy foliage.

While poison hemlock is commonly seen along streams, roadside ditches, and other moist areas, it takes root just as easily in meadows and backyards.

Farmers need to ensure that it doesn’t get mixed with hay and that animals in pasture do not eat it. As few as 100 grams of the leaves can poison a sheep, and 300 grams can poison a cow. Symptoms can appear within an hour after ingestion, and death from respiratory paralysis can occur in 2 to 3 hours.

To get rid of poison hemlock it is advisable to hire a landscape contractor that is certified in pesticide application, or to do it yourself use Roundup or a 2-4-D herbicide designed to kill broadleaf plants. Do not burn or hand-weed poison hemlock. Wear long sleeve shirts, long pants, shoes, socks, and nitrile gloves while using herbicides.