Contributor: Deborah Landau, The Nature Conservancy, MD/DC chapter, dlandau@tnc.org
As temperatures begin to rise and we start looking for signs of spring, don’t be fooled by these little yellow beauties as you stroll through the woods looking for wildflowers. Lesser celandine (Ficaria verna), is a member of the buttercup family and more commonly known as fig buttercup. It is a non-native invasive that will quickly out-compete our native spring ephemerals and many more native plants in our natural areas. Introduced into the United States in the late 1800’s from Europe and parts of northern Africa and Asia as an ornamental, this plant creates thick mats across the forest floor, crowding out other vegetation above ground, and growing tubers below ground that compete with plants for root space. The plants are highly visible in early spring, which is why they have been selected as Maryland Invasive Species Council’s March Invader of the Month.
The attractive bright yellow flowers have eight to 12 petals and are about 3 inches across, blooming from late winter to early spring. After flowering, the shiny, dark green kidney-shaped leaves carpet the forest floor until the mid-summer. The thick tuberous roots, about a half an inch each in size, form a dense network below the soil surface. By June, the foliage has died back, and the plant becomes dormant, though the tubers continue to occupy root space below ground year-round. Lesser celandine primarily reproduces through these underground tubers, so disturbance, including pulling, flooding and digging by animals can result in further spread of the plant.
Because lesser celandine emerges so early, it can out-compete many native ephemerals, taking advantage of early-season sunlight before trees begin to leaf out. The resulting dense mat formed will shade our native spring wildflowers, preventing them from emerging, and likewise disrupting native pollinators searching for early-season nectar sources.
Lesser celandine can be controlled chemically or manually. For chemical removal, a 1-2% glyphosate solution can be applied during the active growing and blooming period, between February-March when temperatures are above 40oF. Spraying during this time will minimize killing other native plants in the vicinity as most should not have emerged yet, but precautions should still be taken to minimize spraying non-target plants. Manual or mechanical removal of small infestations can be successful but removing all the below ground parts is critical. This plant will readily reproduce vegetatively, so any missed roots or tubers can produce new plants.
To help ensure long-term success, after removing lesser celandine, replant the area with natives, which will to help control soil disturbance and replenish an important nectar source for insects. Lesser celandine is often confused with a desirable native wetland plant called marsh marigold (Caltha palustris). While they have similar leaf shapes and color, marsh marigold flowers only have five to nine petals and the plant does not produce tubers. Other native alternatives to consider include wild ginger (Asarum canadense), bloodroot (Sanguinaria canadensis), twinleaf (Jeffersonia diphylla), cutleaf toothwort (Cardamine concatenate), Dutchman’s breeches (Dicentra cucullaria), Virginia bluebells (Mertensia virginica) and golden ragwort (Packera aurea).
Maryland banned the sale of lesser celandine beginning in 2017. However, it may still be commercially available in other states, and all varieties should be considered invasive.
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