Don't be Deceived by This Beguiling Springtime Plant

Many people look forward to seeing the first flowers emerge in spring, and there are indeed many lovely plants appearing this time of year. However, this is also the time to be on the lookout for a nasty invader: lesser celandine (Ficaria verna) (synonym=Ranunculus ficaria), also called 'fig buttercup.'

What Is It?

Image: Lesser celandine can form extensive mats and is especially problematic in floodplains and riparian zones, where flowing water helps move the plant to new locations. Credit: Emily Rojik

Lesser celandine is a spring ephemeral, meaning it emerges early in spring before trees leaf out, but it doesn’t stick around very long. The leaves and flowers of spring ephemeral plants are generally gone by late May in Pennsylvania, but their underground parts continue to store nutrients for re-emergence the following spring. Native to parts of Europe, Asia, and northern Africa, lesser celandine was introduced to North America as an ornamental during the 1800s and has become widespread in the northeastern and mid-western United States. This invader is most prevalent in floodplains, moist lowlands, and riparian areas near bodies of water, but it can also be found in upland areas with drier soils. Lesser celandine will also invade lawns and gardens. Unfortunately, this plant is still available for sale in the nursery trade.

How to Identify It

Image: Look for celandine’s small kidney-shaped leaves and yellow flowers. Credit: Emily Rojik

To spot lesser celandine, look for a low-growing plant with glossy, kidney-shaped leaves up to 4 inches high, with bright yellow flowers on stalks that can reach 9 inches tall. The flowers resemble buttercups, and lesser celandine is, in fact, in the buttercup family (Ranunculaceae). Lesser celandine reproduces and spreads through seeds, tubers (underground, fleshy, bulb-like structures), and bulblets (small bulb-like structures that grow on the stems). These multiple reproduction methods help lesser celandine become an aggressive spreader and form dense mats that cover large areas if left unchecked. These mats can inhibit or prevent the growth of native plants, especially native spring ephemerals such as spring beauty (Claytonia virginica), Dutchman's breeches (Dicentra cucullaria), squirrel corn (Dicentra canadensis), and others.

Image: Marsh marigold can be distinguished from celandine by its finely toothed leaves, flowers with more rounded petals, larger stature, and growth habit of individual plants rather than a ground cover. Credit: Emily Rojik

When looking for lesser celandine, be careful to not confuse it with marsh marigold (Caltha palustris), a charming native that looks very similar to lesser celandine. To tell them apart, look closely at the leaves, the edges of which are usually smooth or gently lobed on lesser celandine, but finely toothed on marsh marigold. The flowers also differ, as lesser celandine usually has 8 narrow, pointy petals (but can have more), while marsh marigold generally has 5 to 9 petals that are more rounded. Additionally, marsh marigold does not form mats or carpets, but rather grows individually, and it will only be found in very wet locations, like swamps and stream banks or lakeshores. If the plant is growing in a drier site, like an upland slope or a lawn, it is most likely lesser celandine.

What Can I Do About It on My Property?

If you positively identify lesser celandine on your property, several control options are available. It is possible to remove small patches by digging them up and sealing all plant parts in a bag for burning or disposal in the trash. However, this method is difficult because all plant parts, including underground tubers, must be removed and properly disposed of.

Image: Bulblets on the stems of celandine will grow new plants. Credit: Leslie J. Mehrhoff, University of Connecticut, Bugwood.org

The most efficient and effective control method, especially for larger infestations, is to spray the plants with a systemic herbicide. The recommended treatment is using a glyphosate product with 41% to 54% active ingredient, mixed in water at 1.5% volume. The treatment window is quite short, starting before the celandine begins flowering and ending when approximately 50% of the plants are in flower (generally late-March through April in most of Pennsylvania). This window helps to minimize the injury to native non-target plants, which usually begin to emerge in late-April to May.

Image: The underground tubers of lesser celandine must all be dug up and destroyed if removing this plant by hand. Credit: Leslie J. Mehrhoff, University of Connecticut, Bugwood.org

Note that glyphosate is a non-selective herbicide, meaning it will injure or kill most green plants that it contacts so it's important to avoid spray contact with desirable plants as much as possible. Alternatively, Ohio State Extension and Clemson University Extension report that the active ingredients triclopyr, 2,4-D, dicamba, and MCPA can also provide control of lesser celandine when at least two of these ingredients are combined in the spray mixture. These are broadleaf-specific herbicides, meaning they will not harm grasses. This may be a good option if you have celandine growing in your lawn. An example of a product that includes triclopyr and 2,4-D is called Aquasweep by NuFarm Inc. This product is labeled for use in turf/ornamental settings, as well as aquatic sites.

Regardless of which herbicides you choose, follow the instructions on the labels. If the celandine is growing near water, be sure to use only aquatic-labeled herbicide products and avoid spraying the water directly. Apply herbicides when the air temperature is at least 50°F and there is no rain forecast for 12 hours. For use in lawns, read the label for specific instructions on different types of turfgrass. Do not mow lesser celandine, as this can actually spread the plant and can also decrease the effectiveness of herbicides.

Keep in mind that control efforts will need to be repeated for at least two years, probably more, especially for larger infestations. Even after the celandine seems to be eradicated, you should continue to monitor the site and surrounding area for several years to ensure that new infestations don’t start up. In natural (non-landscaped) settings, such as riparian areas, seeding the area with native grasses and sedges after a season or two of celandine suppression could help to compete with the celandine. You can then continue treating the celandine with broadleaf-specific herbicides while the native grasses provide a native groundcover.

What Can I Do About it on Other Property?

Image: This screenshot of the EDDMaps website shows the confirmed lesser celandine reports in North America by county.

If you positively identify celandine somewhere other than your own property, you can't do any removal of it yourself, but you can report it, which is still very helpful to land managers. If you find celandine on public land, report it to the agency or organization that oversees the land. Additionally, whether you find the celandine on public or private land, you can report it through EDDMaps (on their website, www.eddmaps.org, or in the smartphone app). Take good photos of the celandine and upload them with your report so experts can confirm the identity of the plant. Reporting invasive plants through this site/app helps agencies and land managers have a better idea of the locations and extent of infestations, which helps them with their planning and management efforts and predicting where the plants may spread.

Image: Although some people may find it attractive, lesser celandine is highly invasive and should be killed wherever possible. Credit: John M. Randall, The Nature Conservancy, Bugwood.org

Additionally, you can help our native ecosystems by spreading the word! Kindly encourage your neighbors and other people you know to suppress celandine and other invasive plants on their properties, and to purchase native plants for landscaping.

Image: Lesser celandine flowers are bright yellow, with darker yellow in the center. Credit: Emily Rojik