Poison Hemlock

(Source: JD Green, Kentucky Pest News)

Poison hemlock (Conium maculatum) is not just a roadside or non-cropland weed anymore!

The invasive weed brought to the US as an ornamental in the 1800s, can now be found growing in pastures and hayfields abundantly. Producers should take note, and be able to identify poison hemlock that could possibly be found growing in hay fields, and take care to mow around the plants or remove them from their fields.

The poison hemlock plants are not typically palatable to livestock with adequate forage to graze, however when the plants are cut and baled with the hay crop, livestock can consume the plants unknowingly.

All parts of the plant, including the seeds are considered to contain the toxic principles. Toxicity may be somewhat reduced in dried plants, but the potential for toxicity still exists in dried hay when a sufficient quantity is consumed.

Cattle, horses, and goats are generally considered to be the most susceptible, however other animals can be affected. For cattle, lethal doses are considered to be in the range of 0.2% to 0.5% of the animal’s body weight. Poison hemlock can also cause fetal deformities when pregnant animals consume the plant.

Poison Hemlock plants are flowering this time of year and are easily spotted with the white flowers appearing on multi-branched stems, and growing to around 6-8 feet tall.

The best control strategy for poison hemlock is to prevent seed formation, as most plants can produce 35,000-40,000 new seeds. After the plants have flowered it is too late to utilize herbicides. Mowing or cutting the plants before peak flower production will reduce the amount of new seeds produced.

Take note of areas on your farm that have heavy populations of poison hemlock this spring and consider spraying herbicide this fall or early next spring.

Young actively growing plants in the rosette stage can be controlled with an application of an herbicide containing dicamba as the active ingredient, in the fall as plants harden off for the winter they can be harder to kill with herbicide, so an early spring application may be the most effective.

For more information on controlling weeds in pastures and hayfields call the Clinton County Cooperative Extension Service at 606-387-5404.

Educational programs of the Cooperative Extension Service serve all people regardless of race, color, sex, religion, disability or national origin.

Upcoming Meeting

Beef Quality and Care Assurance training

A Beef Quality and Care Assurance (BQCA) training will be held on Thursday, June 7th at 1:00 pm and 5:00 pm at the Clinton County Extension Office. Producers that will be receiving cost-share through the CAIP program will need the BQCA number for the large animal investment area.

The training cost is $5 for materials and will be valid for three years.

If you plan to attend the training please call the Extension Office at 606-387-5404 due to limited space.

BQCA trainings will be held monthly starting in the fall and running through the end of the CAIP program, there will be several more opportunities to get CAIP cost-share education.