Invasive Species, Pesky Plants by Chris Kjolhede

Velcro: Inspired by the Common Burdock

As one of four brothers within five years of age, we all knew about burdock. Most importantly, we knew how to gather the burrs into baseball-sized clumps and hurl them at each other. These missiles were pretty harmless but clung to sweatshirts, sweaters and long hair. I suspect that our family alone is responsible for a great deal of the spread of “common burdock” in the Midwest where we were raised.

Common burdock, Arctium minus, often locally called “wild rhubarb,” is native to Eurasia as are many of our other local invasive plant species. Burdock was likely an early invasive carried by livestock owned by European immigrants. Sheep’s wool was a likely means of transport. Even today, burdock burrs find their way onto sheep where they diminish the quality and the value of the wool.

Burdock is a biennial. The first year it appears as a floret of heart-shaped leaves low to the ground. Some leaves can be over a foot long. The second year, the plant sends up a stalk as high as five feet with clusters of pink and purple flowers. These mature into the barbed burrs that contain seeds. One plant can produce as many as 15,000 seeds. Burdock can often be found on roadsides, in disturbed soils, and in feed lots and pastures where it crowds out native grasses.

Removing burdock plants can be a three-part process. During the first year of life, when the plant is small, hand pulling may work if the soil is moist. Second-year plants can be removed by severing the taproot with a spade several inches below the soil. I find using a round shovel is most effective since my soil is very rocky. And lastly, flowers and burrs can be cut and burned; do not put them in your compost pile as they may germinate.

Burdock has some positive uses. Its roots have been used in herbal preparations as a diuretic and for some skin problems. Some East Asian cuisines use the tap root in food preparation. The Velcro inspiration, huh? The next time you encounter burdock burrs, look very closely. The end of each of the many tiny spines is curved back on itself, just waiting to affix itself to some fabric or animal fur. This was noted by George de Mestral in 1941, when he examined burrs on him and his dog. Yup! Early Velcro!

Chris Kjolhede, MD, MPH, is an emeritus pediatrician at Bassett Healthcare Network.