Community Agriculture Alliance: It’s late, but not too late
July 3, 2014
Houndstongue (Cynoglossum officinale L.) goes by other names, as well: houndstooth, dog's tooth, dog's tongue, dog bur, gypsy flower and rats and mice (because of the smell of the leaves). By whichever name, the plant is a highly invasive, toxic biennial threatening pasture and rangeland, hay meadows, gardens, lawns and roadsides.
This alien invader originally came from southeastern Europe and southwestern Asia.
The first mention of this alkaloid rich plant occurs in Shakespeare's “MacBeth” as an ingredient in the witches brew. Folk medicine has suggested several possible uses for houndstongue including; lung disease persistent cough, piles, sores, baldness and ulcers.
In the 1725 Dictionaire Oeconomique, an ointment made from the plant was indicated as part of a cure for madness, which also required the placement of a live pigeon or hen on the patients shaved head.
Maybe madness is as madness does!
The alkaloids present in the plant tissue do cause irreversible liver damage, especially in horses, and though unlikely to be grazed, it is dangerous in hay where selectivity is more difficult or in corral confinement. Always remove this weed from corrals before confining animals.
Recommended Stories For You
The first North American report was from Ontario in 1859, and houndstongue had become the predominant weed in Michigan by 1861, according to Henry David Thoreau during his travels there.
The first Western occurrence was reported in Oregon in 1893, and the weed now is present in every state except Hawaii.
As a Colorado list B noxious weed, a management plan for its control is required for each county. It is one of Routt County's 13 noxious weeds as designated by the county commissioners, and it is the responsibility of every landowner or manager to control the weed on their property.
The plant poses challenges for control, but some plant attributes make control very straight forward.
The main challenge is the number and easy transportability of the seed, as dogs, horses, livestock, wildlife and ourselves brush up against the standing dried seed stalks and move the seed wherever we go.
Whenever you see these flat burs clinging to your dog, horse or yourself, stop and take a few minutes to remove and secure the burs for disposal.
The favorable factors for control include the biennial life cycle that gives one full season and the following spring/early summer to control the plant prior to seed development.
Once the seeds hit the soil, virtually all germination occurs in the first year if covered by a half inch of soil or litter.
Fewer than 10 percent of any seeds that don't germinate the first year of soil contact will ever germinate.
Be diligent. Don't ignore control efforts. A herbicide mix of 2,4-D and Escort works well, and though it's getting late to spray flowering plants, we still have time to spray the rosettes or use a shovel and a bag to remove mature plants.
With any luck, we may soon have a bio-control, a native tiger moth caterpillar from Yellowstone (currently under evaluation), to help us control houndstongue.
Greg Brown is a member of the Community Agriculture Alliance board of directors and Supervisor of the Routt County Weed Program.