Buttercups may evoke images of childhood innocence, but in reality, the plant can be deadly for livestock. Tall buttercup in particular is classified as a noxious weed, and is a serious weed problem for forage producers in western Alberta.
Tall buttercup is a member of the Crowfoot family, which includes native plants such as anemone, columbine, monkshood and larkspur. The weed was introduced from Europe and has no natural disease or insect enemies in Canada.
The plant has been in Clearwater County for over 25 years. There are currently about 10,000 to 15,000 acres of the plant in Clearwater County and the weed has been found in the neighbouring counties of Yellowhead, Brazeau, Wetaskiwin and Red Deer.
This is a plant that really likes moist, well-drained soils so it is very suited to the eastern slopes with the large amount of moisture we get and the very organic soils we have, said Matt Martinson, assistant manager of Agricultural Services with Clearwater County.
Tall buttercup can be poisonous to cattle and can have a negative effect on horses. In general, most cattle will refrain from eating it, but it can cause sores in their mouths if they consume it.
It could potentially kill a calf, but probably not a large animal. But it certainly has made high-value horses sick, said Martinson.
Tall buttercup is invasive, reducing biodiversity in grassland.
We re certainly seeing it spread through our country at an alarming rate, just as wild caraway and oxeye daisy has, said Martinson.
Tall buttercup seeds can be transported as they get hooked on the coats of livestock and wildlife. The seeds are also carried easily by water and can be transferred in hay crops. The seed can remain dormant for about 10 to 12 years if buried deeply.
The plant can reach full maturity by mid-July, and the weed can spread quickly.
Tall buttercup can be controlled by herbicides and integrated weed management. The window for optimum control is narrow.
Unfortunately, you can t mow tall buttercup like you can thistles and you can t graze it because it s poisonous, said Martinson.
Goats and sheep seem to be immune to the effects of tall buttercup and can be used to graze the plant. However, they need to graze the area hard so that they do not select for grasses. The grazing option could work on a small-scale basis.
Herbicide is the predominant management tool.
Herbicides get a bad rap, but they can be used properly in a very sensitive area, said Martinson. Restore or Grazon are options. Restore has no grazing restriction, but cattle should not be on the land when the herbicide is applied to the land because it will irritate their eyes.
Clearwater County has specialized equipment that allows spraying of herbicides on hard-to-access terrain. This equipment has been used on large grazing reserves throughout the province and has been rented by other counties.
We re fairly well known for having specialized, custom-built equipment in the province for range pasture herbicide applications, said Martinson.