Birdsfoot Trefoil

A man examines the Clay County Birdsfoot Trefoil field, 1950 (Ozzie Dahlenbach Collection, HCSCC).

Birdsfoot Trefoil
Mark Peihl
July 16, 2020

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Every year around this time, a low growing plant with lovely golden-yellow flowers covers the boulevards along Moorhead’s streets. You’ve probably seen it. The plant forms a thick mat, often draping gracefully over the curb and onto the street. It’s called Birdsfoot Trefoil (Lotus corniculatus), a species introduced to provide forage for livestock. In the 1950s, it briefly became a specialty crop, raised for its seeds — and Clay County was a leader in its production.
 
Birdsfoot Trefoil forms multiple inch-long seed pods radiating from the tips of its stalks. Some people think this looks like a bird’s foot. The Trefoil part of its name comes from the three leaflets on each leaf. It is a remarkably adaptable plant that is native to most of Europe, much of Asia and north Africa. One theory suggests that its initial US introduction could have come from ship ballast dumped along the Atlantic coast and the Hudson River. By the early 1930s, it was firmly established in two locations, western Oregon and eastern New York state.
 
In the early 1930s, a New York Soil Conservation Service agronomist recognized its potential value as livestock feed. He arranged for boys enrolled in the Civilian Conservation Corps to hand harvest wild seeds and had them planted in test plots. Birdsfoot Trefoil is a legume. Like alfalfa and clover, it captures nitrogen from the air and fixes it in the soil, fertilizing it. Tests showed that Birdsfoot Trefoil provided good forage, could be grown on poorly drained and alkaline soils ill-suited to alfalfa and, unlike clover, did not cause a fatal digestive disease in livestock called bloat.
 
Seeds from New York and imported from Europe were sent to test facilities around the country. In 1938, a test plot in Winona proved it could be grown in Minnesota.      
 
In 1941, newly hired Clay County Agricultural Extension Agent G. E. May began a successful program to get farmers to improve the quality of their pastures. The drought of the 1930s left many pastures in rough shape. May encouraged farmers to plow up their grasslands and replant with mixtures of grass and legumes. In 1948, a handful of Clay County farmers began planting regular test plots and incorporating Birdsfoot into their mixes. The mix did well, once it was established.
 
By 1950, there was a run on BIrdsfoot seed. Ag Agent May, in his 1950 Annual Report wrote, “About a year ago, Birdsfoot Trefoil was mentioned at every opportunity in discussing pastures. When it was learned the seed source was very limited and that it was extremely high priced, everyone’s mouth began to water, they wanted some seed. They have had several doses of ‘you can’t have it yet but wait.’”
 
Farmers in Norman County began raising Birdsfoot for seed. In 1955, they formed the Red River Valley Certified Trefoil Seed Growers Association to promote its production and establish standards for certified seed. That year, Herman Lee of Felton planted forty acres. Art and Hank Skolness of Glyndon put in several hundred. Neil Peters of Moorhead later put in eighty.
 
As a new crop, it came with a steep learning curve. The NDAC Extension Service published a how-to circular on raising Birdsfoot but it proved to be a finicky crop to produce. It required chemical weed control to get established and if harvested when it was too dry, the seed pods popped open, spilling the seeds prematurely. Herman Lee harvested his first crop in 1956 when the seeds had a fairly high moisture content. He managed to get a respectable 625 pounds per acre. Certified seed sold for $2.00 per pound in Fargo that year. He spread the seeds out on the floor of a Quonset building to dry but they over heated and much of his crop did not match the Association’s germination standard.
 
In a wet year like 1958, Birdsfoot produces a lot of foliage. It can take a long time for it to dry enough to cut properly. But by then, the pods are too dry and they pop. Neil Peters tried to make the harvest easier by spraying a defoliant on the crop. The top leaves dropped off but the seed pods popped, too. Peters lost 2/3 of his crop.

Birdsfoot Trefoil growing along Moorhead’s 1st Ave N just east of the Hjemkomst Center, July 1, 2020 (HCSCC).

The Skolness brothers had better luck. In 1957, they told new Clay County Ag Extension Agent Ozzie Dahlenbach they expected to harvest six to seven thousand pounds of the Viking variety and twenty-five to thirty-thousand pounds of the Empire strain. Empire is a low growing cultivar best suited for grazing. Viking is a taller standing variety better for cutting as hay. Dahlenbach reported that the brothers “have put in a complete processing unit which will take care of practically all the cleaning jobs that one might run into in processing the seed.”
 
Despite the problems, in 1958, Clay County farmers raised 85% of the seed submitted for certification testing in Minnesota. But by 1959, the price of Birdsfoot Trefoil dropped by half. Though farmers continued to use it in their pastures, production for seed disappeared. After 1960, Extension Agent Dahlenbach never bothered to report BIrdsfoot Trefoil as a specialty crop in Clay County.
 
Today, Birdsfoot Trefoil is found in nearly every Minnesota county. It spreads easily and is difficult to eradicate. It’s especially problematic in virgin or restored prairie environments where its dense mat chokes out native species. The Minnesota Department of Agriculture has assessed Birdsfoot through its noxious weed regulation evaluation process and recommended that it “not be regulated to continue to allow its use in agronomic grazing systems.” However, it recommended “that people do not intentionally seed Birdsfoot Trefoil in fields adjacent to native prairie management areas and do not include Birdsfoot Trefoil in wildlife or deer seed mixes.” U of M Extension Ag Educator for Clay County, Randy Nelson told me he did not know of anyone in the county intentionally growing Birdsfoot, though there may be some out there. Various cultivars are available from regional seed houses.
 
Though it’s probably not a good idea to plant it in your yard, there are no rules against enjoying Birdsfoot Trefoil’s lovely flowers where they are. Invasive or not, they are a sure sign of early summer in Clay County.