by Connie Oswald Stofko
Lesser celandine is an invasive weed that can take over your lawn and gardens.
“Whatever you do, don’t ignore it,” said Master Gardener Lyn Chimera.
It’s pretty, but…
Lesser celandine (Ficaria verna, formerly Ranunculus ficaria) is easy to ignore, Chimera acknowledges. It’s a spring ephemeral and dies back, so it’s easy to forget about it once it disappears–but it will return.
And because it’s pretty, many people don’t recognize it as a weed. Chimera was one of these people. Twenty years ago, she saw the plant blooming in her mother-in-law’s yard.
“It grows in shade and was beautiful, so I dug some up and planted it in my garden,” Chimera said. “I thought it was marsh marigold.”
Chimera is still trying to get it out of her yard.
It’s horrible, too!
Lesser celandine spreads exponentially, doubling every year, Chimera said.
It can reproduce in three ways:
- Tubers on the roots. They look like tiny potatoes. If you don’t dig up every single tuber, you’ll get new plants. It’s easy to miss some tubers because they are so small.
- Bulblets on the leaf stalk. These bulbets fall off easily.
- Seeds. When the plant flowers, it produces seeds. If the plant is near water, the seeds can be carried downstream. Birds that eat the seeds can also poop them out far from the original plant. (Because bird poop is a good fertilizer for plants, the seed comes out covered in fertilizer, Chimera noted. Sigh.)
“It spreads like crazy” in wild areas, she said, and out competes native plants. Lesser celandine gets a headstart because it comes up early in spring. It also has a dense root system that chokes out other plants.
If you leave it in your lawn, you’re going to have an unhealthy lawn.
How to get rid of lesser celandine
Timing is important.
If you want to use an herbicide, you must use it before the plants flower. Herbicides won’t work after the plant flowers. See details below.
Other methods are best done before the plants flower, too.
Dig it all up
Chimera suggests digging up lesser celandine.
It’s important that you get as many of the tubers as possible. Dig around the plant as far as the leaf mass goes, she said.
Don’t knock the extra soil off the plant. Place the plant, soil and all, in a plastic garbage bag.
“It makes for very heavy bags,” she acknowledged.
Gardeners hate to part with their good soil, but the soil could contain tubers that you have missed.
Try to dig up lesser celandine before it flowers. Otherwise you may be dropping those bulblets from the leaf stalks into your garden.
Don’t try to pull the plant out; you’ll leave tubers behind.
Carefully dispose of the plants so they don’t spread. Don’t put the plants in your compost and don’t put them out for your town to pick up with yard waste such as sticks. Put your plastic bag out with your trash to go to a landfill.
You can use an herbicide, but it must be applied in early to mid-April, said Andrea Locke, coordinator of WNY PRISM (Partnership for Regional Invasive Species Management). If you wait until you notice the flowers, it’s too late.
If you spray the plants with an herbicide after they flower, you can kill the leaves, but it won’t kill the tubers. The plants will just come back next year.
Common active ingredients found in herbicides for lesser celandine are triclopyr, glyphosate and dicambia, she said. You can find these herbacides in garden centers and other stores.
You may have to apply again the next year.
Follow the directions carefully when using any herbicide.
Don’t use vinegar
One reader was considering using industrial strength or horticultural vinegar on lesser celandine. Chimera doesn’t suggest using it on lesser celandine for several reasons.
Horticultural vinegar is 10 to 20 percent acetic acid.
“It’s very toxic and it can burn your skin,” Chimera said, and it’s more harmful to animals than synthetic herbicides.
Perhaps more to the point, horticultural vinegar doesn’t work on lesser celandine. When you spray it on the leaves, the leaves will die, but not the tubers. The plant will just grow back. (Household vinegar, the kind you have in your kitchen, won’t work, either.)
If you drench the soil with horticultural vinegar, you’re killing all the beneficial microbes in the soil that your plants need to grow.
Chimera doesn’t use synthetic herbicides such as glyphosate, but “it has its place, and this is one of them,” she said. “It’s a personal decision” on whether you want to use a synthetic herbicide.
If you are faced with a large garden bed filled with lesser celandine, smothering may be your best best.
First, dig out any perennials you want to save. Hose off all the dirt from the roots to make sure there are no lesser celandine tubers hitching a ride. Place your perennials in pots.
Then take lots of newspaper (several days worth, Chimera says) and lay it on top of the plants. (She prefers newspaper over cardboard because it gets soft after a year and you can cut through it more easily when you want to install new plants.) Make sure you overlap the newspaper so there are no seams or openings where the lesser celandine can get through.
Add two to three inches of mulch on top.
Set your pots on top of the mulch. It will still look like a garden. (See how a Buffalo gardener used this technique to kill grass.) When the lesser celandine is dead, replant your perennials back into the bed.
You can use this technique on your lawn, but you will have a swath of mulch on your lawn. Still, that may be better than lesser celandine.