By Deborah White, Kentucky Native Plant Society Board
By the end of winter, we are looking for any hope of spring, any bright color in the landscape we can find. When you see a pretty yellow flower in late winter, check to see if it is lesser celandine (Ficaria verna) before you get excited.
Description
The leaves of this invasive plant emerge in winter, and they cover the ground quickly, outcompeting many native plants. This pest plant has a single yellow flower at the end of a stem. It is closely related to buttercups (its former name is Ranunculus ficaria, and sometimes it is called fig buttercup) and, like buttercups, the flower has many stamens. There are seven to thirteen flower petals. The leaves are medium to dark green, generally heart-shaped and not lobed with wavy edges that have smooth or rounded teeth. Also, the small bulbils at the base of the plant will help identify it (see also the control section as these bulbils allow this weed to spread).
Habitat
Lesser celandine grows in riparian areas like stream banks and adjacent flat moist areas, shady woods and even lawns. Lesser celandine is found in the eastern United States, west from Texas and Missouri, as well as Washington and Oregon on the west coast.
How it Got Here
Lesser celandine is native to Europe, Asia and Africa. Introduced to the United States for horticultural use as a border plant, this weedy invasive is, unfortunately, still being sold. It easily escapes from gardens to nearby forests. The fingerlike bulbils and fruit can be spread by flooding, or any movement from one habitat to another, even mowing.
Ecological Impacts
Lesser celandine can quickly form a blanket across the ground in natural areas. It crowds out native plants and depresses their reproduction. Like other invasive weeds, the elements that control these plants in their native range, whether fungus, animals or other biological controls, are absent, leaving this plant free to increase, unchallenged.
How to Control
Small infestations may be removed by pulling the plants by hand, but all plant parts must be removed to be effective. The roots and bulbils easily fall from the plants and then establish new plants!
It is also possible that covering the plants with black plastic to solarize, or heat up the soil can help kill the vegetative structures and root systems of the plants. This would be appropriate where lesser celandine is abundant.
Studies show spraying with herbicide is effective, especially if applied before other plants have emerged. Glyphosate has been used to control lesser celandine but be aware that it is not appropriate for use near aquatic habitats. A 2.5% solution may be applied when it is at least 50 degrees Fahrenheit–being extra careful to spray only lesser celandine because the herbicide will affect any plant it contacts. It may take two or even three applications and future monitoring to eliminate the plants. You will be helping our natural flora by battling this yellow invader!
References
Aulakh, Dr. Jatinder S. Lesser Celandine (Ficaria verna Huds.) Identification and Management. Connecticut Agricultural Experiment Station.
Plants for a Future. Accessed 4/2/2021 Ficaria verna https://pfaf.org/user/Plant.aspx?LatinName=Ficaria+verna
Washington State Noxious Weed Board. Lesser Celandine. https://www.nwcb.wa.gov/weeds/lesser-celandine-1
Invasive Plant Corner: Lesser Celandine (Ficaria verna)
At the end of winter we are looking for any hope of spring, any bright color in the landscape we can find. When you see a pretty yellow flower in late winter, check whether it is lesser celandine (Ficaria verna) before you get excited.
Deborah has been a botanist for the Kentucky Office of Nature Preserves and Florida state plant conservation programs.