Fillmore County Journal

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April weed of the month: Lesser celandine Lesser celandine, also known as fig buttercup, is a relatively new invader to the state

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Lesser celandine, left, and marsh marigold, right, are often mistaken for one another. However, there are differences when observed closely.

In a few short weeks (or longer in the northern part of the state), we will begin seeing the pops of color of spring ephemerals. Some skunk cabbage is already taking advantage of areas with recent snow melt. As the snow recedes and the ground temperatures begin to warm, the beginning of spring is a great time to look for the emergence of invasive plants.

Lesser celandine (Ficaria verna), also known as fig buttercup, is a relatively new invader to the state. It is a great example of a plant to watch for in the spring. Early spring detection allows for quicker management response and targeted treatments before other desirable plants begin to develop and flourish.

Lesser celandine has a very short lifecycle, growing as soon as the snow melts and dying back to its underground roots by June. iNaturalist photos from an infestation in Saint Paul show that its bloom time varies greatly in the state. One post shares blooming lesser celandine on March 26, while another shares it is blooming on May 6. Environmental conditions influence blooming times, but being prepared earlier in the spring will allow for greater management success. It is also important to familiarize yourself with native plants that look like invaders such as lesser celandine.

The aerial bulbils form at each leaf node of lesser celandine and can be quite numerous on individual plants.
Photo submitted

A plant that you may find blooming at the exact same time as lesser celandine is the native marsh marigold, Caltha palustris. Marsh marigold is generally larger than lesser celandine, and it grows in bunches. Lesser celandine is low-growing and will form dense mats. Marsh marigold has only five petals on its showy yellow flowers, and lesser celandine has 7-11 petals. Lesser celandine also has a glossy shine to it, while marsh marigold does not. If you’re still not sure what you’re looking at, look below the flower petals. Lesser celandine will have three green sepals, marsh marigold doesn’t.

Because of lesser celandine’s short growth window, there is little time to find and control new infestations. Its main method of spread is vegetative by underground tuberous roots and aerial bulbils at the nodes. This makes it difficult to control effectively. Control and monitoring efforts will need to be repeated for several years.

Small populations can be hand-pulled effectively, though care must be taken to remove all the tuberous roots. Larger populations can be controlled effectively with herbicide – contact your local University of Minnesota Extension office or see the below links with information for recommendations.

Lesser celandine is a Restricted Noxious Weed in Minnesota as of January 1, 2023. For more information, please see: dnr.wisconsin.gov/topic/Invasives/fact/LesserCelandine.html and www.dnr.state.mn.us/invasives/terrestrialplants/lesser-celandine-invasive-species.html.