Silver Cinquefoil is another European invader that was probably brought to North America as a medicinal herb — long enough ago that some regions consider it to be a native plant.
According to the American Invasive Plant Atlas, most Silver Cinquefoil infestations are in the Great Lakes and New England areas, where early pioneers likely planted it in their herb gardens and then allowed it to escape into nature.
The Idaho and Washington State areas, next to our border, are also Silver Cinquefoil hot spots.
It has become a problem weed in Grand Forks area alfalfa fields.
This invasive weed, with little yellow flowers that have five petals alternating with fivepointed hairy sepals, and the five-leaflet, deeply notched palmate leaves that are dark green on top, and covered with dense silvery white or gray hairs underneath, first came to my attention when a friend, with an acreage along Hidden Valley Road, asked for help with a plant that was forming thick mats in her pasture that were smothering the grass.
The five or so mats of cinquefoil covered about half an acre of her pasture. Native cinquefoils don’t do that.
It turned out to be Silver Cinquefoil —listed as a Weed to Watch Out For in my 2011 edition of Invasive Plants of the Crown of the Continent manual.
You can download a pdf of the manual from this website. www.nps.gov/glac/learn/nature/upload/Reprint-Weed-field-guide_web.pdf
Now that Silver Cinquefoil is on my radar, I am noticing it starting to grow along the gravel shoulders of my street and into people’s driveways. You can be proactive like me, and dig this taprooted invader from gravel or moist soil, with a screwdriver, before it spreads. For larger dense mats of Silver Cinquefoil, a broadleaf herbicide, like Killex, will control the invasion.
Weed Warrior Frank
