After a long winter, who doesn’t love happy yellow flowers that pop up and fill your garden?
The answer is you—if the flowers are lesser celandine (Ficaria verna, previously Ranunculus ficaria L.). (It’s also known as fig buttercup.)
Lesser celandine—native to Asia, northern Europe, and northern Africa—was probably imported to the States for ornamental use in the 1800s. Today, the invasive perennial can be found in most states east of Missouri, the Pacific Northwest, and Texas.
Why is this little flower such a big problem?
Because they grow and bloom in mid-March, earlier than other spring ephemerals, and form thick mats that crowd out all other plants—including native ephemerals. Being spring ephemerals themselves, once done, they leave blank spots open for weeds to take root. The pretty little menaces also thrive in a variety of soil conditions, and in both sun and part shade. They can outcompete the grass on your lawn.
How to identify:
Lesser celandine forms a low mounding mat that can quickly take over a garden or field. Its leaves are kidney-shaped and held up on long stems in very dense basal rosettes. The flowers are mainly a bright yellow. A very similar native wildflower is the marsh marigold (Caltha palustris). While they look very similar, the main way to tell them apart is that the marsh marigold follows about a month after the lesser celandine in most areas. Also, lesser celandine has bulblets for roots, whereas the marsh marigold does not. Still not sure? Check the suspect plant out with a plant ID app.
How to remove:
Smaller patches can be removed by hand. But remember to get all the bulblets. Do this before it flowers. The flowers can form aerial bulblets. Lesser celandine is a starfish of the plant world—the smallest bit left behind is enough to grow a new plant. Throw it away with the garbage; do not compost.
Larger infections can be controlled by using glyphosate, an herbicide, judiciously. Timing is everything. Lesser celandine comes in very early, before the natives. Treating the plants with herbicides ideally before they flower and before other desired plants wake up is very important.
Targeted applications are a must. Painting, not spraying, the herbicide ensures you are killing only the lesser celandine and not your other garden plants. Follow directions exactly, paying special attention to temperature, wind, and proximity to bodies of water. Most herbicides are highly toxic to fish and amphibians. This treatment could take several years to completely eradicate the plant. (Go here for a first-person account of using glyphosate herbicide to kill lesser celandine.)
What to replace it with:
Now if you do like the cheery yellow flowers, you can still have them! Once you clear the area, fill it with marsh marigold or Chrysogonum virginianum, another nearly identical native (a reader points out: “You have to look twice to see which is which!). Other native ephemerals are American ginger (Asarum canadense), Dutchman’s breeches (Dicentra cucullaria), cutleaf toothwort (Cardamine concatenata), spring beauties Claytonia virginica, trilliums, and bloodroot (Sanguinaria canadensis).
- Wild Flower Society: 10 Outside-the-Box Native Plants
- 10 Native Alternatives to Invasive Plants
- The Garden Decoder: What Are ‘Native Plants’?