How do I control poison hemlock and wild parsnip?

Question:

How do I control poison hemlock and wild parsnip?

Answer:

Control of wild parsnip (Pastinaca sativa) and poison hemlock (Conium maculatum) is the same.  Safely removing these weeds from the landscape is important as both species can be toxic to humans and animals.  

Control of this weed takes special care.  It is important to reduce contact with these species by doing things like wearing good waterproof gloves, long sleeves & pants, protective eyewear, and closed-toed shoes.

Wild parsnip plant parts contain a substance called psoralen, which can cause skin reddening, rashes, and blisters when sap or juice from the plant gets on the skin and the skin is exposed to sunlight.  All parts of the poison hemlock plant are highly toxic to humans and animals and may result in death if ingested. Because plants look similar to edible species of the carrot family, occasionally, plant parts are mistakenly ingested.

These weeds persist in the landscape through the spread of seeds.  Elimination of seed production and spread is the goal for managing these weeds.  Management techniques to eradicate wild parsnip and poison hemlock include discouraging growth and development through dense competitive plantings of desirable plants, carefully pulling and digging, mowing to prevent seed set, and herbicides.  This often has to be done over several weeks as plants do not all bloom at the same time.

More information about how to identify these species of weed can be found in the links below:

More detailed information on controlling these weeds can be found in this article: Control of Wild Parsnip.

Answered by
  • Specialist
  • Consumer Horticulture Extension
Last updated on
April 29, 2024