08.29.06
Poisonous Cowbane Growing in Gilford N.H.
We’ve heard about local lakes’ milfoil problems, but there is another noxious plant spreading on land in Gilford, and this plant is highly toxic to livestock and even people if eaten. Spotted Water Hemlock, aka. Cowbane, is present in Gilford; owners of cattle, horses, sheep– all grazing animals– and also hay farmers should be aware.
Water Hemlock, cicuta maculata, was identified on Schoolhouse Hill Road over a year ago by the county extension service. It is considered one of the most poisonous plants in the U.S., containing a deadly toxin which affects the central nervous system when ingested. The roots of the Water Hemlock have a high concentration of cicutoxin, and ingestion of even small amounts can be lethal. One gram of Water Hemlock per kilogram of body weight will kill a sheep, and eight ounces (approximately 230 grams) is enough to kill a horse.
Article in Laconia Citizen (will request you to sign in to read)
Poisonous Water Hemlock, aka. Cowbane, grows up to 6 feet tall in Gilford NH. Leaves in bottom third of photo are the cowbane foliage; the flower spikes grow very tall above the thickest area of the branches. You may find plants without any flowers, because it is a perennial which flowers in its second year (we believe.)
Fresh leaves and stems can be deadly when browsed, especially in the spring. Animals have been poisoned by drinking water that had been contaminated with trampled Water Hemlock roots. Humans have died after only one or two bites of root, which they mistook for wild parsnip or artichoke.
Related to the parsnip, carrot and parsley family, Cowbane can grow up to 6 feet high; it produces white blooms similar in appearance to Queen Anne’s lace in late summer, and is easiest to spot right now while in bloom. It has leafy lower foliage and thick, sometimes purplish-marked or mottled, hollow jointed stems; broken stems may exude yellowish oily or watery liquid smelling like parsnip.
Cowbane blossoms, similar to Queen Anne’s Lace
Water Hemlock occurring in hayfields causes some concern. If cut in a hay crop, drying reduces the above-ground Cowbane’s toxicity; its toxic properties are lower later in its season as well. Therefore, Cowbane in hay might not cause clinical toxicosis. However, should the Cowbane’s roots, which are NOT made less toxic by drying, enter a hay harvest (such as through cultivation,) there would be considerable risk to the hayfed animals.
Cowbane grows in damp, marshy areas, and the recent rainy summers have helped it to spread locally, often into stream banks and roadside drainage ditches. Stands of Water Hemlock/Cowbane have been identified in the following locations in Gilford (and may be in other areas as well):
Schoolhouse Hill Road
Gunstock Hill Road
Watson Road
Gilman Road
Old Lake Shore Road
Cherry Valley Road at 11B junction
In controlling the Cowbane’s spread, precautions should be taken, according to Doug Cygan, New Hampshire Dept. of Agriculture (contact info below):
Wear rubber gloves, and avoid skin contact with sap, especially to face or eyes– when it’s flowering, there is also chance of a dermal (skin) reaction to the pollen;
Use spade or tined fork to uproot the plant and remove its branching root system;
Place plants in black plastic trash bags;
Place bags in the sun to “cook” for a few days to dry out the plants;
They may then be disposed of in regular trash.
Stem structure, thick and hollow, distinctive joints
As concerned horse owners, my husband and I, along with several of our neighbors, are working to mow down large patches of Water Hemlock and also to pull up individual plants. We urge other area residents to help curtail the spread of this dangerous species immediately, while it is easiest to identify and before full bloom is past, when it will spread even further.
Find more information and more photographs of poisonous Spotted Water Hemlock see here:
Purdue Univ. report
all-creatures.org
survivalIQ website
N.C. State Univ. Horticulture Dept.
photos, CT Botanical Society
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Please note that Emails, calls or letters of concern to Doug Cygan below will help to focus the state’s attention onto this New Hampshire problem.
Doug Cygan 603-271-3488
Invasive Species Coordinator
State of N.H. Dept. of Agriculture
Division of Plant Industry
29 Hazen Drive
Concord, NH 03301
Email: dcygan@agr.state.nh.us
Website– general N.H. info, invasive plant species list for N.H., etc.: N.H. Dept. of Agriculture
Detail of Cowbane/Spotted Water Hemlock leaf structure
as posted in equinesite.com by petArtist
as submitted to local newspapers by Connie Moses
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Connie Moses, petArtist– self-built website: PortraitsWithHorses.com
(horse and pet portraits)
