Nature News: At what point should we give up trying to control the invasives?

published June 24 2021 in The Portsmouth Herald, York Weekly, Fosters’ Daily and other Seacoast Media Group newspapers and online.

I’ve been driving back and forth to Manhattan fairly frequently to visit my aunt and like to spend some of the long drive checking out the vegetation growing in the various rest stops.  There is one pretty little clover-type plant growing in both my super-sandy scrubby field and in most of the roadside rest stops and median strips, bird’s-foot trefoil (Lotus corniculatus), that I decided to investigate further.  This is not the lotus blossom famous for its beauty or, in Greek mythology for its narcotic powers (check out the Lotus Eaters of the Odyssey fame), but rather the name given to the genus of a group of plants in the pea family.  The species name, corniculatus, refers to its common name ‘bird’s-foot’ in reference to the ripened seed pods which curve outwards resembling a bird’s foot, each toe curved like a talon (hence “corniculatus” meaning small horns).  The “trefoil” part of the name, which means ‘three leaves’ is a misnomer, these actually have 5 leaflets, three prominent ones and two hidden beneath.  

Bird’s-foot trefoil are beautiful, aggressive, soil-building, nitrogen-fixing non-natives -sue pike photo

3-foot taproots, fibrous mats of rhizomes–yikes!!

If you take a close look you’ll see that they do have clover-like leaves and flowers that resemble most of our other wild peas.  Sadly, they are non-native, have spread throughout the United States and up into Canada and Alaska and are considered noxious invasives in some states.  A native of Europe and Asia, they were introduced as forage for livestock. With their 3-foot taproots and fibrous mats of rhizomes they can quickly take over an area, smothering other native species.  

Considered edible but all parts are poisonous

I thought, since they are in the pea family, they might be edible. Here’s where it got interesting.  After some intensive googling I found one of my favorite descriptions of its edibility:  “Bird’s-foot Trefoil, Lotus corniculatus, is a member of the Pea Family and has been considered both edible and medicinal but be aware that all parts of this plant are poisonous.” (  This is one of those plants that contains small amounts of cyanogenic glycosides (cyanide) that are not a huge issue in small amounts (and have been used medicinally in the past)  but can be lethal to humans if enough is consumed.  However, for wildlife it is a different story; bird’s-foot trefoil  is considered a choice food by Canada geese and deer and attracts a variety of pollinators.  

Most of the flowers in my meadow aren’t native anyway….

While I would love to have only native species growing in my yard, I would guess that at least 50% of the plants growing in my field/lawn are non-native.  This is partially because these mowed fields are not a native habitat to this area and so attract and support any non-native open field plant that can get a toe-hold.  I am trying to figure out whether to control this plant to keep it from dominating the field, reducing the overall biodiversity, or to eradicate it completely. Given that we have nutrient-poor sandy soil that many plants don’t like to grow in to begin with, and, as a legume it is a nitrogen-fixer, I’m leaning towards controlling but not eradicating it.   In addition, bird’s-foot trefoil has beautiful clusters of bright yellow pea-like flowers shot through with streaks of red which the bees, wasps and other pollinators seem to love as much as the dandelions, butter-and-eggs toadflax, black-eyed-Susans and daisies that populate the field, which, by the way, are also non-natives.