I have a problem with lesser celandine in my garden. How can I get rid of it?
— Fran Gordon, Skokie
I noticed lesser celandine sprouting in my garden a couple of weeks ago, so it is time to begin control measures. Lesser celandine (Ficaria verna) is a very invasive spring ephemeral perennial plant that has become more prevalent in gardens and lawns. Leaves begin to emerge before flowering in very early spring, so look for it before other plants have started to grow. It will form large, dense patches in your garden so best to watch for it and eradicate even very small clumps of it as you see them. You can also find it growing in the crowns of perennials and bases of shrubs. Because lesser celandine emerges well in advance of native and ornamental species, it has a developmental advantage that allows it to establish and overtake areas.
Plants consist of a basal rosette of succulent, dark green, shiny, kidney- to heart-shaped leaves that will creep across lawns and beds. The flowers are easy to recognize with eight (typical) to 12 bright yellow petals arranged symmetrically around a slightly darker center that rise above the leaves on single stalks. The foliage begins to die back after flowering and will mostly disappear by June or earlier if temperatures are consistently warm. Lesser celandine spreads primarily by vegetative means through prolific tubers and bulblets, each of which can grow into a new plant once separated from the parent plant. The tubers may be unearthed and scattered by the digging activities of animals, as well as weeding, and spread to new sites during flood events.
For small infestations in garden beds, lesser celandine may be dug up using a hand trowel or shovel. It is very important to remove all bulblets and tubers, as each one left in the ground can grow into a new plant. For example, rototilling a bed will simply propagate this plant with a bunch of small plants coming back the following year. You will need to be persistent in removing this weed in future years to eradicate it. I have had success in eliminating this weed from vegetable garden beds by weeding it out year after year. All parts of the plant must be bagged up and disposed of properly in the garbage. Do not put it in a compost pile. Large infestations in a garden are very time-consuming to dig out.
Due to its short life cycle, the window of opportunity for controlling lesser celandine is limited, but it can be accomplished with persistence over time using methods that are appropriate for the site and size of the infestation. It is best to spray as soon as you see the leaves emerging, as once the plants begin to flower, herbicides will be much less effective and the chance of damaging adjacent good plants greater. While manual removal methods are possible for small garden infestations, the use of systemic herbicide is more effective because it kills the entire plant, including the roots and minimizes soil disturbance. You can expect to treat plants two to three times each year over a period of years to get this plant under control, if well established in your garden. Lesser celandine can be easily confused with marsh marigold (Caltha palustris), a native plant found in wetland habitats and in some home gardens with moist areas.
It’s important to apply the herbicide just as the lesser celandine begins growing for the best control and to minimize the impact on adjacent desirable plants. Start applications prior to flowering and up until about 50 % of the plants are in flower and then stop. I usually make two to four applications in my garden beds as more plants continue to sprout over time. Applications can be made early in season when the temperature is 40 degrees Fahrenheit or above, and no rain is anticipated for 12 hours. It is best to use a spreader sticker with the herbicide since the leaves of lesser celandine have a waxy covering that repels water. Glyphosate herbicide is systemic with the active ingredient absorbed by the plant and will eventually kill the plant. Re-treatment over the following years will likely be necessary. Because glyphosate is a nonspecific spray, it should be applied so that it contacts only lesser celandine and does not drift onto desirable plants such as turf grass or perennials.
I have been using a product called Sure Power for the lesser celandine growing in my lawn, which seemed to knock it back more dramatically than other products I have used in past years. The lesser celandine has unfortunately returned this spring to my lawn. It is too soon to tell if any progress has been made in controlling it. I plan to continue treating with Sure Power in future years and have opted not to use the non-selective herbicide glyphosate to treat the lawn. It’s important to read the label on whichever herbicide you decide to use to make sure you are using it properly and safely.
For more plant advice, contact the Plant Information Service at the Chicago Botanic Garden at plantinfo@chicagobotanic.org. Tim Johnson is senior director of horticulture at the Chicago Botanic Garden.
