Thursday, March 31, 2016

Alert: Monitoring for Lesser Celandine

Memory was finally jogged that this is the time of year to be scouting Princeton's natural areas for the dreaded Ficaria verna, a.k.a. fig buttercup, or lesser celandine. Dreaded because it has an alluring yellow flower that makes one want to leave it be when it starts showing up in the yard or local preserves, but then quietly takes over, paving whole valleys. Pettoranello Gardens is carpeted with the plant. In Durham, NC, I once tracked an infestation upstream to a homeowner's yard. He was greatly relieved to find out what plant had taken over his garden, and proceeded over the next several years to completely eliminate it. Unfortunately, by then the plant had spread far downstream and would transform a whole watershed, from one small infestation in someone's yard. He was, however, able to remove some he had put in his son's yard elsewhere in town, before it had a chance to spread downstream. This is why it's so important to get the word out about these highly deceptive species.

When I was working at Mountain Lakes, I'd walk the valley leading down from Stuart School, searching for any small patches that could be eradicated before they expanded beyond remedy. It's satisfying to be able to nip invasions in the bud. Now that my focus is Herrontown Woods, the spring ritual is playing out there. Yesterday's walk yielded no sightings until the very end, when I checked the pawpaw patch we planted New Year's weekend, and headed back through the woods towards the parking lot. There, right where the groundwater seeps out of the ground in what originally may have been a primitive septic system, was a patch of lesser celandine. Already, it has spread down the ditch about fifty feet, but is still of a size that we can eradicate it before it spreads down the valley, beyond control.

Control options can be found at this link. A comparison of lesser celandine with other yellow spring flowers, such as marsh marigold and celandine poppy, can be found here. If possible, avoid hiking through an area with lesser celandine--there's a risk of inadvertently spreading it into new areas in the treads of your shoes.


  1. The link to control options doesn't seem to work. I'm very interested in that--there's a relatively small patch of lesser celandine in Barbara Smoyer Park, which I am hoping to conquer in the next few weeks.

  2. Thanks for pointing out the inactive link! I've been emailing the parks department about infestations in Smoyer and Harrison Street Parks. A town council member said "this stuff has spread into and all over my yard from an adjoining park. My landscape architect and my landscaper had very different views when it first appeared ten years ago. My LA was alarmed and wanted to be quite aggressive. The landscaper was more relaxed, and as a cancer survivor, she is slow to use pesticides. I wish I had been aggressive."

    You're on the right track to work to eliminate it before it spreads. I'd encourage you to contact the Rec Dept. and coordinate your efforts with them. Hopefully they will respond quickly enough to allow action asap, well before the leaves fade in early summer. I searched the internet. The You Bet Your Garden site is useless, as they've succumbed to the same skewed logic that has affected the judgement of the NY Times science section. I'm not familiar with treatments for lawns, but below is a state extension recommendation. The sooner this spring something can be done, the better.

    These links are two versions of the same recommendation. Spray with glyphosate, which is the active ingredient in Roundup, but can be bought under different names. It's the additives, not the active ingredient, that determine whether aquatic life is harmed, and I doubt there are any frogs in these upland parks. Rodeo is the wetland-safe version, if one wants to be cautious. Treatment has to be done in spring, before the leaves die back.

    In turf/lawn settings products containing at least two of these herbicides have been found effective. The herbicides to look for are MCPA, triclopyr, dicamba, that will remove many broadleaf weeds. Glyphosate products are non-selective and will destroy desired species. This process will take seven to fourteen days. No selective post emergent is currently labeled for this plant. - See more at:

  3. Steve thank you for the alerts about this pesky invasive -- playing croquet in the garden of friends, we saw lesser celandine taking over as their unplanned ground cover; felt ungracious alerting them but relieved not to see it on our own property--until today when I found a patch here. Yikes! Luckily it still seems isolated and I have sprayed every leaf I could find - can see how it was beginning to spread, fiendish stuff. I know little about gardening and would have felt sinful using Roundup except for your timely warnings and information!

    1. Good to hear from you, Callie. Yes, ungracious is what I feel too, when I point things out, but I think people appreciate being alerted. It's a very deceptive plant.