Controlling buttercup is no laughing matter

Q: I have a weed that appears in my yard every spring, and each year it takes over more of the lawn and the beds. I believe it is officially known as lesser celandine. It has a pretty yellow flower and bulbous roots. By late spring, it usually dies back, only to return with a vengeance the next year.

Recently, I noticed its leaves in the lawn already. Is there anything I can do now or in the spring to eliminate this weed without destroying my lawn or the plantings in the beds? I have tried pulling it out, but there are now too many and I suspect pulling them out may cause it to spread more. I have tried Weed B Gone with limited success. I'm reluctant to use a product like Roundup because of its effect on the nearby grass and plants.

A: Lesser celandine (Ranunculus ficaria), better known to homeowners as buttercup, is a non-native herbaceous perennial brought to the United States from Europe as an ornamental plant. That means it's very likely that at some point someone intentionally planted it in your yard or nearby, probably for its attributes as a vigorous-growing groundcover.

It also has been paid homage by at least one song, and even has its own old wives' tale: For some reason, it was widely believed by the superstitious that holding the bright yellow blossom under one's chin would reveal his or her penchant for butter. Really.

But controlling lesser celandine is no laughing matter. For small areas, digging up the weed deeply enough to remove all its tubers and bulblets can be effective. But hand-pulling can actually exacerbate its invasiveness in larger areas like yours, as inadvertent separation of bulblets or tubers from stems will encourage propagation.

Triclopyr, an ingredient in some selective broadleaf post-emergent herbicides such as Ortho's Weed B Gone for Difficult to Control Perennial Weeds, or clopyralid, the active ingredient in Lontrel, are effective means of control, according to the Cornell University Landscape Horticulture Program Work Team. Be sure to follow package directions carefully, knowing that more is not better. Herbicides containing 40 percent glyphosate, the active ingredient in Roundup, also have been shown effective in controlling lesser celandine, but as you pointed out, extreme care must be taken to avoid contact with surrounding plants and grasses.

For best results, spray in March, April or May. However, as long as rain isn't in the forecast and the temperature is above 50 degrees, you can treat the plant during winter.

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