Poison hemlock spotted locally
Auglaize Agriculture and Natural Resources Extension Agent Jamie Hampton warns Poison Hemlock has made an appearance in Auglaize County this year. As producers begin to harvest hay and silage, control of this noxious weed should be addressed.
General Description:
Poison-hemlock is a biennial that produces leaves in a basal rosette during its first year and forms an upright flower stalk when it bolts during the second year of growth. Poison-hemlock has dissected leaves, which resemble those of parsley, and umbrellashaped clusters of small white flowers that are like flower clusters produced by many other species in this family. However, the stems and leaf stalks (petioles) of poisonhemlock differ from other family members in that they are hairless and have distinctive purple spots or blotches. If bruised, the plant emits a mouse-like odor.
Toxicity:
All parts of the plant contain toxic substances that cause respiratory failure in humans and other animals if ingested. Seeds and roots are more toxic than foliage. Toxins are also present in greater amounts in plants grown under sunny compared with moist conditions. The taste of leaves and seeds of poison-hemlock is reported to be unpleasant, so toxic quantities are seldom consumed. Still, poison-hemlock leaves are easy to confuse with those of parsley, seeds resemble those of anise, and roots look similar to parsnip roots. Animals may be induced to eat this unpleasant plant because it is often one of few plants remaining green in winter and among the first to resume growth in the spring. According to the USDA, cattle can be poisoned from eating as little as 300-500 grams and may die within a few hours after consumption. Toxicity changes little if plants are fermented with silage or dried in hay.
Control:
Control of Poison Hemlock can be accomplished in many ways. Poison Hemlock can be removed manually by pulling, digging or cutting it out. Mechanically with mowing or using a handheld weed eater. Chemically with herbicides that contain 2,4-D, Dicamba or Glyphosate containing chemicals.
Cautions:
Poison Hemlock can cause some people to experience skin irritations. It is important to use person protective equipment. Plant material that has been manually or mechanically removed should be bagged or piled and burned since it is highly toxic and could pose a danger to wildlife, livestock, and children.