Will the Real Marsh Marigold Please Stand Up--a Confusion of Yellows

A lot of people call this flower "marsh marigold". It's not. Notice the leaves stay close to the ground, and the small flowers have many petals. This plant is actually Lesser Celandine, a pretty but highly invasive exotic plant that will spread across lawns and coat floodplains in what looks like green pavement. I found this one specimen in my yard, and because there was only one, I was able to dig it up, hopefully before any seeds were produced, put it in a plastic bag, and threw it in the trash, not the compost.

(Update: Most homeowners don't notice lesser celandine, also called fig buttercup or Ficaria verna, until there are too many to dig. Digging also requires getting every last tuber in the roots. Oftentimes, the only practical option is to use a targeted dose of herbicide. Though herbicides are demonized due to their overuse in agriculture, the selective use of low-toxicity herbicides is an important part of invasive species control, just as low-toxicity medicines are selectively used in medicine. I use a 2% wetland-safe version of glyphosate, which can be bought from companies other than Monsanto.)

The real marsh marigold, shown here, is a native with five-petaled flowers, stands more upright, and is so rare that I've only seen it growing wild once in my life. These particular plants are in my backyard, purchased from Pinelands Nursery in Columbus, NJ. I also planted some at the Princeton High School Ecolab Wetland that are in full bloom right now.

The flower and leaf of marsh marigold (Caltha palustris) are on the left, with lesser celandaine (Ranunculus ficaria) on the right.

Dandelions blooming now can make it harder to tell if you have lesser celandine in your yard.

Adding to the confusion of yellow this time of year is the Celandine Poppy (Stylophorum diphyllum), a native in the poppy family that was common in the University of Michigan arboretum, but seldom seen elsewhere. A friend in Princeton gave me some, and it has seeded into the flower bed of my backyard. Like the marsh marigold, its rareness in the field bears no relation to its willingness to grow when planted in the backyard.

Be On Guard for Lesser Celandine

(This post is from 2021. Click here for more recent posts about nature.)

From backyards to front yards to curbsides to parks and nature preserves, a small invasive flower is on the march. Dominating the landscape in early spring with its yellow blooms, it turns March into LOOK AT ME, ME, ME!, because that's all you will see when lesser celandine coats the ground. Just to hoodwink homeowners, the name "lesser celandine" has sometimes been supplanted by the name "fig buttercup," but it's all the same plant, whose latin name is Ficaria verna. 

My posts about the plant date back to 2007, when I heard people mistakenly calling it "marsh marigold," which it most emphatically is not. Back then, lesser celandine was most entrenched at Pettoranello Gardens and rapidly spreading downstream into Mountain Lakes. Hopefully, when Princeton hires an open space manager, a more coordinated effort can be launched to reduce the plant's spread and protect areas not yet infested. Homeowners tend to like the plant at first, then become appalled as it begins taking over the yard and spreading to the neighbors'. 

Use herbicides on lesser celandine? The nature of good and evil.

Those who care enough about their yards and the local ecology to want to stop the plant's spread may also feel qualms about using herbicides, which are the only practical means of control. Removal by digging is cumbersome, time-consuming, and adds unnecessary weight and bulk to your trash can. I encourage people to think of herbicides for nature the same way we think of medicines for people. We know all medicines have some level of toxicity, but we use them in a minimal and targeted way to protect our health. Doesn't nature deserve the same sort of intelligent intervention? It's important to make a distinction between spot spraying for lesser celandine and the blanket application of pesticides and chemical fertilizers on lawns. If treating lesser celandine that has invaded lawns, use an herbicide that is selective for broadleaf plants so that the grass survives. If there's just one plant here and there, spot spraying each plant with glyphosate, the active ingredient associated with Roundup, should kill the plant without harming surrounding grass. 

Update, April 2025: If you're dealing with low ground near water, there are so-called "wetland-safe" formulations of herbicide, usually obtained online. AquaNeat is an example of wetland-safe glyphosate, which needs to be diluted to 2% to spray on the leaves. A Penn State webpage recommends Aquasweep for treating lesser celandine in lawns. Though I have no experience with dealing with a lawn that has been completely taken over by lesser celandine, one option could be to have a landscaper treat the lawn with Aquasweep or similar. Any approach will require some followup, but each year will get easier. Though spraying may be more effective earlier in the spring, it should be possible to have an impact as long as the leaves remain green. Check back in a week to catch any that were missed.

While avoiding blanket condemnations of herbicides, I also like to avoid thinking of invasive species as "bad plants." Like so many of the problems that plague us, they are "too much of a good thing." Unfortunately, though it might be tempting to keep a few lesser celandines in the yard, its super aggressive behavior makes that very risky. Best to eliminate it altogether. Winter aconite, on the other hand, is a nonnative that has a flower very similar to that of lesser celandine but has not to my knowledge spread into natural areas.

Selected past posts:

2019: Fig Buttercup--Little Flower, Big Problem - Photos of fig buttercup's (lesser celandine's) spread, along with a discussion of why this invasive species creates more problems than other common invasives.

2018: A World Paved With Fig Buttercup? - Lesser celandine's other common name is fig buttercup. This post documents in photos and text the astonishing spread of this plant in the Mountain Avenue neighborhood.

2017: Winter Aconite and Fig Buttercup--Related Flowers, Contrasting Behaviors - These two early blooming yellow flowers look very similar, but behave very differently.

2016: Letter On Lesser Celandine Strikes a Nerve - a letter in the Town Topics that got quite a response

2016: Alert, Monitoring for Lesser Celandine - This post includes links to treatment options.

2015: Marsh Marigold vs. Lesser Celandine - Lesser celandine is frequently mistaken for the native marsh marigold, which is a larger plant and very, very rarely seen.

2013: Will the Real Marsh Marigold Please Stand Up--a Confusion of Yellows - Some photos help distinguish lesser celandine from marsh marigold, dandelion, and celandine poppy.

2007: Pretty, but... - My earliest post on lesser celandine.

Sweetgum: Embedded Mysteries of a Tree and Its Rare Paneling

A tree can be many things for many people: beautiful or a nuisance, its wood low-grade or its grain profound. A sweetgum tree is all these things for me. This post will give you a tour through sweetgum's beauties and annoyances, including its surprising use as high-end wood paneling in the 1920s and 30s.

First, regard the beauty. What other tree offers such a panoply of colors in the fall? Yellows, reds, purples, orange--sweetgum does it all. True, those powerful colors are only generated by trees that receive adequate sunlight, but there is some wonderful, creative chemistry going on there. Carotenes, xanthophylls, anthocyanins--these are the words that exercise the tongue while stirring curiosity about the possible purpose behind all that color.

There was a time in my life, during my extended undergraduate career, when I acquired a fascination with chemistry, specifically organic chemistry--the chemistry of carbon, the element upon which life is built. While premeds labored through the lectures with high anxiety for the grade they might receive, I was there with a love of subject and a hunger for knowledge.

In decades since, and not talking about premeds here, I've noticed that people who are disconnected from nature tend to be intimidated by nature's complexity. In order to feel comfortable, they surround themselves with a simplified, static nature of mowed lawn and trimmed shrubs. But for those of us who love nature, its complexity is appealing--a richness that rewards endless inquiry and exploration. I remember a bus ride through New England, probably in my 20s, looking out the window and thrilling at the thought of all the chemistry going on in the forested hillsides we were passing by. 

At the same time, it's hard not to be annoyed by the sweetgum's "gum balls" scattered on the ground, prickly and destabilizing underfoot. (Update: A friend says he collects them in winter to use for starting fires in the wood stove.)

Overabundance, too, can turn affection into surfeit. In the piedmont, stretching from central New Jersey down through North Carolina, sweetgum sprouts like a weed in areas we seek to maintain as meadows. Managing remnant piedmont prairies at Penny's Bend in Durham, NC, required mowing or prescribed burns to keep the rampant growth of sweetgum seedlings from smothering rare wildflowers. Grasslands in NJ often require similar intervention.

At least near water, one natural check on sweetgum's rampancy is beavers, who apparently love them for their inner bark laden with sweet gum--the liquid amber found in its latin name, Liquidambar styraciflua. This photo was taken during a walk at Plainsboro Preserve ten years ago. The beavers' preference was so strong, and the sweetgums so numerous, that we saw no other species of tree being chewed upon.

The vexing ubiquity in early succession that I've encountered in the eastern piedmont contrasts strikingly with my experience with sweetgum years prior in Ann Arbor, MI. Being a more southern species, the tree's native range doesn't extend into Michigan, so it's no surprise that a horticultural colleague at the University of Michigan proudly planted a sweetgum as something rare and wonderful, with its fall color and craggy winged stems. 

The sweetgum's wood, too, generates conflicting impressions. It rots quickly if left on the ground, is hard to split, and proves insubstantial as firewood. 

And yet, fifty years ago, my family moved into a beautiful house in Ann Arbor that was paneled in the most appealing way with sweetgum. The wood had a rich, warm glow--clearly a winner for paneling, but I have not knowingly encountered it since.

Then in 2023, we discovered a piece of wood from a packing crate bearing the name Demarest and Co on a wall inside the Veblen House. While researching the Demarest name, I came across an article about American Gumwood. In 1926, the Bureau of the Hardwood Manufacturer's Institute in Memphis, TN was promoting its new booklet: Beautiful American Gumwood: A superb native hardwood for interior woodwork and furniture.  

It took awhile to figure out that they were talking about sweetgum, not another eastern native called black gum. As a friend pointed out, calling sweetgum "gumwood" also risks confusion with the eucalyptus native to Australia, sometimes called gum tree.

The pamphlet begins by describing America's great forests as being our destiny to harvest. I've included long quotes to get a sense of the rhapsodic language.

The story of American gum wood dates back many centuries. Nature requires many years of favorable growth to produce a masterpiece, and in the vast stretches of our southland forests, extending from the Atlantic to the Mississippi valley and beyond, the quiet work of building cell and fibre was going on long before DeSoto and his valiant men first beheld in wonder the mighty "Father of Waters." What a marvel of creation, when from soil, moisture, and sunshine this fine wood came into being, now to be transformed by the hand of man into products that contribute to his well being and enjoyment.

By the mid-1920s, apparently, that enthusiastic harvest had led to more preferred species growing scarce:

Lumbermen have long known gumwood, yet vast tracts have been left standing while other interspersed hardwoods of widely varying species which happened to be wanted at the time, have been cut out. 

Overlooked in the past, sweetgum now stood ripe for the taking.

The tree itself, as it displays its lofty and graceful symmetry, is one of the glories of our native forests. Its sturdy proportions are enhanced by masses of scarlet, orange, and yellow leaves, which change, as the summer wanes. In size, it is heroic; one hundred feet to one hundred fifty feet in height, with a diameter of four or five feet, is not unusual. And some idea of the extent of growth of this important tree may be gained from the fact that with the exception of the oaks, gumwood exceeds all other hardwoods.

If sweetgums could read, they might have felt deeply flattered, but also be wondering if their tombstones were being readied and inscribed. And yet, one cannot be fully dismissive towards tree harvest--we who live in wooden houses and keep ourselves warm through the winter with fossil fuels rather than renewable energy from wood. 

This photo in the pamphlet looks reminiscent of the warm glow of the paneling I experienced fifty years ago, but doesn't capture the complexity and variety of mysteriously generated grains that sweetgum is capable of.

As the pamphlet explains:

Now no wood has more wonderfully interesting patterns than figured gumwood, but it is one of Nature's riddles to account for them. The pattern is not produced in the usual manner by quarter-sawing, although this process will improve any figure if it is already there. All one can say is that some trees have pronounced figured wood, others varying degrees of pattern, and many which show but slight indications of it. Undoubtedly the condition of the soil and the location of the individual tree affect in some mysterious way the structure of the wood. Only when the tree is felled, does the grain show itself as plain or figured. That is what makes the gumwood tree so interesting; it is like finding a }ewel, the value of which depends upon hidden qualities brought out by cutting and polishing.

The quizzled, tangled grain that makes sweetgum hard to split can bedazzle when milled. As with fall leaf color, the sweetgum's grain will vary tree to tree.

The figure ramifies through the wood at random, obeying no known laws. Gumwood logs will each display differing patterns, some subdued, some intricate and ornate.

Go forth, then, dear readers, and if you happen upon a sweetgum along a trail at Herrontown Woods or elsewhere in Princeton, slowly reaching for the dimensions the pamphlet describes, know that you are gazing upon a mystery of creation, whose creative chemistry is not yet fully understood, and whose sometimes plain, sometimes profound grain is impossible to predict from one tree to another.

There's one more passage in the pamphlet that helped me understand why my family home in Ann Arbor was paneled with sweetgum. The 1926 pamphlet may have influenced the couple, Walter and Martha Colby, who built the house in 1933, but they may also have encountered the paneling during their many travels in Europe. The pamphlet explains:

Europe has long recognized the exquisite beauty and texture of American gumwood. In fact, England, France, Italy, Spain, and other countries were first to recognize its fine working qualities. In America, however, its light was for a time hid under a bushel, so far as public acquaintance with its true worth is concerned. But now, due to growing appreciation of its merit, the valuable products of the gumwood tree stand forth proudly as "American gumwood,'* nothing else -so named, and so prized. The old adage, "a prophet is not without honor, save in his own country," no longer applies, if we may adjust this metaphor to a tree.

Here's a career move that musicians know well--a wood that needed to cultivate an audience abroad before it could be valued at home.

Winter Aconite and Fig Buttercup (lesser celandine)--Related Flowers, Contrasting Behaviors

Both of these non-native wildflowers are in the family Ranunculaceae. Both bloom early and have pretty yellow flowers. While one appears to be modest and highly local in its spread, the other spreads so quickly across yards and into neighbors' yards and floodplains as to pose a threat to gardens and natural areas alike.

Here's winter aconite (Eranthis hyemalis) opening up a week ago in my garden, a legacy from the previous owner. Its modest spread is easily contained. I've never seen it spreading into nature preserves. Note the leaf shape, which distinguishes it from the related wildflower below.

Update: For comparison, here is one of the first blooms of lesser celandine in 2021, on March 30. Note the shape of the leaves, which are "entire" rather than lobed. Just to confuse things, lesser celandine is also called fig buttercup, and its latin name Ranunculus ficaria has apparently changed to Ficaria verna. 

People think lesser celandine is pretty, transplant it to their gardens, then begin having regrets as it spreads uncontrollably to dominate their gardens and yards. If you are one of the distraught gardeners wishing you didn't have this flower, and not wanting to impose its spread on the rest of the neighborhood, late winter is the time to deal with it. 

Other posts on this subject can be found on this website by typing "celandine" into the search box. A post called "Will the real lesser celandine please stand up--a confusion of yellows" helps with identification.

Though I'm no fan of herbicide, that tends to be the only workable option in the majority of cases. I'm no expert on herbicides, but have been told that for lawns, a broadleaf herbicide like Weed Be Gone is effective. For flower beds, a 2% formulation of glyphosate (Roundup or equivalent) works well. Monsanto doesn't hold the patent any longer on glyphosate, so it's possible to buy if from other companies on the internet. I use a wetland-safe formulation, but for most yards, away from wetlands, some spot spraying with Roundup or equivalent should be okay. The plant itself is poisonous to wildlife. 

There have been other proposed means of killing the plant: 

Mulch

If you blanket the whole infestation thoroughly with mulch, e.g. a layer of cardboard covered leaves or hay or woodchips, it might kill the lesser celandine if you mulch as soon as the plants leaf out in late winter. Chances are, you won't cover it soon enough, or you'll miss some spots, and the lesser celandine will benefit next year from the fertilizer in the mulch. 

Vinegar/salts/detergent

This concoction has shown up on the internet: 1 gal white vinegar, 2 cups Epsom salts, 1/4 cup Dawn dishwashing detergent in a hand held 2 gal pump sprayer. Spray in bright sun on a windless day.

But I couldn't find evidence that it has been carefully tested, nor that it would kill the roots. If the roots survive, the plant will be back next year. The concoction contains an acid, and the salts are made of magnesium and sulphates. These may or may not be harmful to the soil if used to excess. 

Lesser Celandine Lookalikes: Which Leaves to Leave

For many people who have a yard to take care of, concern about the ultra invasive lesser celandine can lead to stepping outside to take a closer look at the lawn and garden beds. 

This is a plant, poisonous to wildife, that seems pretty at first, 

then becomes a menace as it spreads through your lawn and flower beds, then into your neighbor's yard and the local nature preserve.

Here's an advanced invasion of a lawn at Pettoranello Gardens.

As you hopefully act to eliminate it from your yard, most practically with a spray bottle in hand, suddenly there's a motivation to distinguish one little plant from another. 

This post will help you make those distinctions between lesser celandine (also called fig buttercup) and other similar-looking plants, and in so doing use as little spray as possible. 

Many people are reluctant to use herbicide, but a yard is not an organic farm. You can't mulch or cultivate a lawn or flower bed, or a nature preserve, for that matter. You can certainly try to dig up lesser celandine, or torch it, or spray vinegar solution. Better results will likely come, however, from targeted, minimalist use of systemic herbicide that kills the roots. Think of the spray not as poison but as medicine. When seeking to heal our own bodies, we catch infections early and use as little medicine as possible to get the job done, and it's the same when sparing nature from invasions. The earlier you catch the invasion, the less herbicide needed, so don't delay.

First, a few photos of lesser celandine in its various forms. Check out the flower in the first photo, here with 8 petals, but often more.

It can have a lot of petals, but they are distinct petals.

By mid-April, the flowers are fading away, so take a good look at the leaf. Invasion of your yard begins with little benign-looking clumps like this, here and there. It doesn't look threatening, but this is by far the best time to act.

Lesser celandine will likely be pretty obvious to you, but if you've been eradicating it each year and are down to a few, it's useful to know other plants that look similar. 

Here's garlic mustard. Notice the scalloped, wrinkled look to the leaves, a bluish tinge, and the strong mustardy aroma. Unlike lesser celandine, which has deeply entrenched roots and no clear rosette, you can gather the basal leaves of a garlic mustard in your hand and pull it out of the ground--something really good to do before it goes to seed, because it too can spread and begin to take over. The smaller leaves closer to the ground in the photo are mock strawberry. See below.

Mock strawberry, a nonnative that can spread in annoying ways, via stolons, through your garden and lawn, has a yellow flower, but only five petals. Note the distinctive leaves, which are composed of three leaflets. 

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Dandelions, too, have a yellow flower this time of year, but you'll see that the dandelion flower doesn't have those distinct petals, and the leaves are not round but instead linear and deeply lobed. Dandelions will invade your yard, but not the local nature preserve.

 

Violet leaves are probably the easiest to confuse with lesser celandine. Notice the arc-shaped veins in the leaves, which lesser celandine lacks. The violet leaves may also be duller--less glossy--than the lesser celandine leaves. Violet leaves and flowers, by the way, are tasty in salads or steamed, so its well worth getting to know them.

Here's a typical violet flower.

Scrutinize this photo a bit. Lower down is the lesser celandine, but in the upper right are two leaves that are similar to lesser celandine, but are more elongated and have ribbing on the leaf surface. 

Here's a cluster of leaves of that other plant that isn't lesser celandine. I don't have a name for it yet.

If you happen upon this one, you've found woodland aster, a native that has white flowers in the fall.

Sometimes I encounter a delicate, usually solitary plant whose basal leaves can look a bit like lesser celandine but with a subtly different shape. 

As it grows, it sends up some creatively shaped avant garde leaves and bears some tiny yellow flowers. I have preliminarily identified it as small-flowered buttercup. It doesn't have the robust, dense growth form of lesser celandine. 

These are the lookalikes that I have encountered. Knowing them helps me use as little herbicide as possible, and save the other plants that increase diversity rather than form monocultures of a toxic plant that's inedible to wildlife.

One more photo showing how those first, benign-looking clumps of lesser celandine, if not dealt with early, will continue to spread and merge into one giant mass that looks like green pavement.

Other related posts:

Will the Real Marsh Marigold Please Stand Up: A Confusion of Yellows