Weed early and often: creeping buttercup

Creeping buttercup (Ranunculus repens).

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Creeping buttercup on May 8, 2018

When creeping buttercups first appeared in my garden, I was inclined to think positively about them. After all, they seemed preferable to pachysandra, which I detest, as a ground cover. I thought they might be hardy geraniums until the yellow flowers appeared. Geraniums have pink flowers. When the stolons, or runners, first became apparent, I wondered if they might be a kind of wild strawberry. Beware of having kind thoughts about cute little weeds in your garden. They will likely grow up to be ugly monsters.

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Creeping buttercups along fence on May 7, 2018

Here is a photo of creeping buttercups in the wildflower corner on May 7, 2018. They are growing along a metal fence, under a lilac bush, around day lilies, and among strawberry plants.

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Creeping buttercups among blue violets on May 7, 2018

They grow readily among blue violets, or any other plant for that matter, as can be seen in the photo above. The King County (Washington State) website wastes no time in describing the negative impacts of creeping buttercups. First and foremost, 1 plant can spread over a 40-square-foot area in a year’s time due to its stolons.

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First root on stolon of uprooted creeping buttercup on May 18, 2018

I devoted over a week of gardening time in early May 2018 to eradicating creeping buttercups from the wildflower corner and, to a lesser extent, from various other sites in my garden. In summer of 2017, I didn’t have much time for weeding, but I did notice the stolons on the creeping buttercups for the first time and got really concerned about their rapid spread. They weren’t creeping. They were bounding. Bounding buttercups.

My solution last summer was to mow them where I could without destroying desirable plants. That was ineffective because they quickly regrow from nutrients stored in corms, or short swollen stems at ground level, as can be seen in the photo below.

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Short, swollen stems of creeping buttercups on May 7, 2018

Creeping buttercups can overwinter as rosettes or die back to ground level. In early spring, before the blooms and stolons appear, they are probably best identified by the swollen stems radiating out from a center rosette. The leaves alone can be deceiving to an untrained botanical eye, looking somewhat like hardy geranium leaves, or like mugwort, or even like parsley. According to the King County website, pale patches on the leaves, as can be seen in the photo above, distinguish creeping buttercups from hardy geraniums.

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Creeping buttercup leaflet at left. Mugwort leaf at right. Although this photo happens to show a difference in size, size is not a reliable factor in identification.

Creeping buttercups are really nothing like mugwort, except in early spring when the untrained eye focuses on individual basal leaves or leaflets instead of the whole plant. I write from personal experience. Whereas the mugwort leaf at right above is a single leaf, the creeping buttercup leaflet at left is part of a compound leaf, as can be seen below. The most distinguishing features, as the season progresses, is that mugwort spreads by rhizomes underground, while creeping buttercups spread by stolons aboveground.

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Compound leaf of creeping buttercup with 3 toothed leaflets, each leaflet with its own stalk

Above is a compound creeping buttercup basal leaf on a long petiole, or stalk, divided into 3 lobed leaflets, each with its own stalk. I have to get used to thinking of that whole structure as 1 compound leaf with 3 leaflets.

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Compound parsley leaf

Above is a parsley leaf, which is also a compound leaf with 3 lobed leaflets. Often, a gardener identifies plants simply because they are in the right place. Right where she planted them, or right where they were last year.

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Creeping buttercup blossom on long grooved petiole, or stalk, on May 8, 2018

The glossy blossoms for which buttercups are named first appeared in my garden this summer on May 8, 2018. The blossoms grow singly on long grooved petioles, or stalks, as can be seen in the photo above. The 5 petals are highly reflective which, among other things, make them difficult to photograph.

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Creeping buttercup bloom reflecting the sun on May 17, 2018

According to a recent study from the University of Groningen measuring light spectra, buttercup petals have a unique anatomy that’s found in butterflies and some bird wings, but is not known in plants other than the buttercups. A layer of air just below a thin one-cell-thick epidermis that contains the yellow pigment causes light to be reflected on both sides of the epidermis, resulting in a white sheen that seems glossy. The study suggests 2 reasons for this unique feature of buttercup blooms. First is that it attracts insect pollinators. Second is that, since buttercups are heliotropic, meaning that the bloom always moves to face the sun, the satellite-dish shape of the buttercup bloom and the glossy aspect of its petals aid in collecting solar energy, which may warm its reproductive organs and hasten the ripening of pollen, fertilization, and seed development. It also must seem nice and cozy to those insect pollinators.

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Buttercup blooms are heliotropic. That is, they follow the sun. The glossy petals collect solar energy, which may enhance fertilization.

According to the Wildflowers & Weeds website, buttercups are a primitive group of plants that have retained most of their ancestral characteristics over time. They are considered simple from an evolutionary standpoint because all their parts are independently attached. Petals, sepals, stamens, and pistils of simple plants are all of an indefinite number and separate from one another. I can’t see this in the photos taken this summer. I’ll try to pay more attention to this fascinating aspect of creeping buttercups next summer. I’m pretty sure they will be back.

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Blossom of uprooted creeping buttercup on May 9, 2018

According to legend, farmers gave the buttercup its name when cows eating buttercups produced the sweetest milk and richest cream. But this can’t be true because buttercups are toxic to livestock, and cows generally avoid them. But you know how legends never die. Holding a buttercup under the chin and seeing a yellow reflection on the skin supposedly indicates a liking for butter. So the legendary associations of buttercups with dairy products seem to persist.

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Creeping buttercups on May 15, 2018

Creeping buttercups are not unattractive, as the sun-dappled photo above suggests. Wildflower or weed. The gardener has to decide. Due to their stoloniferous habit, they are a weed to me. I should add a note here, however, that not all buttercups have stolons, only creeping buttercups (R. repens). Weeds of the Northeast, my goto weed book, also describes bulbous buttercups (R. bulbosus) and tall buttercups (R. acris). Both have the unique buttercup blooms without the stolons. I might consider those to be wildflowers and nurture them if they ever show up in my garden.

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Indian mock-strawberry on May 8, 2018

Early in the week of my creeping buttercup eradication project, I focused on any small yellow flower. But I soon discovered that many plants with yellow flowers looked more like wild strawberries, as can be seen above. Weeds of the Northeast identifies these yellow-flowered plants as Indian mock-strawberries. Wild strawberries have white blossoms. The dainty yellow flowers are quite different from the glossy yellow flowers of creeping buttercups. I quickly became accustomed to identifying which was which in a glance, helping me feel a little more in control of my eradication project.

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Photo on September 1, 2018, of area of wildflower corner where creeping buttercups were manually eradicated in May 2018 and area covered with wood chips

When I finished digging out creeping buttercups from the wildflower corner, I covered the area with wood chips and started searching the remainder of my garden for smaller infestations of creeping buttercups, reminding myself that a single plant can cover a 40-foot-square area in a single summer. Creeping buttercups spread by seed as well as stolons. Seeds are dispersed by birds, squirrels, chipmunks, and boots, as well as wind and water. Seeds remain viable in soil for many years. Once a single plant is established in a new area, stolons provide the means for covering an ever-larger area. In the fall and winter, stolons often fall off, leaving each new daughter plant with the potential of future seed dispersal and multiplication by stolons the following year. What an amazing survival strategy.

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Blooming creeping buttercup among many other plants, mostly weeds.

My eradication project turned from drudgery to adventure as I started searching for single creeping buttercup plants throughout my garden. If they were blooming, I simply had to distinguish them from the yellow blooms of Indian mock-strawberries. Always with a sharp-pointed trowel in hand, I could quickly but carefully dig out the plant–roots and stolons and all–dispose of it in a nearby yard-waste trash can–we have lots of those–and continue my search. This was a good time to put Mrs. Magnus Olson’s dictum to work. As I have mentioned in other posts, in a 1971 letter to Organic Gardening magazine, Mrs. Olson claims that she achieved a weed-free garden by always pulling 10 weeds whenever she stooped to pull 1. As can be seen in the photo above, finding 10 weeds to pull or dig out is not difficult.

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Compound leaves of creeping buttercup in among sweet woodruff, Indian mock-strawberries, and irises on May 21, 2018. The 5 visible compound leaves are radiating from just 1 center.

If the creeping buttercups weren’t in bloom, it was necessary to detect the compound leaves in among other plants, as can be seen above.

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Corm, or swollen stems, of creeping buttercup, hiding out in sweet woodruff patch on May 21, 2018

Here is a closer view of the corm, or swollen stalks, at the center of the creeping buttercup in the sweet woodruff patch.

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Uprooted creeping buttercup plant discovered in sweet woodruff patch on May 21, 2018

Above is a photo of the uprooted creeping buttercup. Notice the stolons already producing the leaves and roots of daughter plants.

On September 2, 2018, after writing the above description of creeping buttercups in the sweet woodruff patch in May of this year, I wandered out to see if all was well with the sweet woodruff. Look below at what I found.

The creeping buttercups were back in the very same spot where I pulled them out last May. Perhaps I broke off a daughter plant and left it behind back then, or perhaps these are from seed. In the photo at right of the uprooted plants, it’s hard to tell which is the daughter plant. They look fragile enough now, but just remember that 1 plant can cover a 40-foot-square area in a season. That fact is burned into my brain it seems.

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Stolon of creeping buttercup uprooted on July 10, 2018

Above is perhaps the longest stolon I managed to uproot. This was on July 10, 2018. Creeping buttercup stolons can be short and thick between nodes, or they can be long and spindly, as above. It seems to depend on environmental conditions, and perhaps the time of the season.

Throughout this summer, in which I was blessed with lots of time to spend in my garden, I found creeping buttercups in a front corner, in the old apple tree area, in the serendipity corner, and, of course, in the wildflower corner where the eradication project got started.

On September 1, 2018, I checked back in the wood-chip covered area where I had hoped that eradication was complete. But no. As can be seen above, creeping buttercups were peeking from under the fence and trying to hide among some Indian mock-strawberries.

Eliot Coleman recommends getting rid of weeds when they are small, definitely a good idea because it’s easier to get rid of weeds when they are small. But what’s good in theory doesn’t always work so well in practice. Weeds have a way of growing while the gardener is busy doing other things. I started a weed hierarchy a few years ago. I rated weeds from 1 to 10. A weed in the 1 category was a non-issue so far as pulling it was concerned. More like a wildflower. A weed in the 10 category had to be pulled or dug up the minute it was spotted. Anything else I was doing had to be dropped and the weed had to be pulled. Mugwort and Japanese knotweed were and are 10s for sure. So now, creeping buttercup is my new 10 weed. When I see it, I pull it or dig it, no matter what. Doing so perhaps saves me a big eradication project the next season, so it’s worth doing. See the post Weeds for more information on my weed hierarchy.

Weed early and often. Especially the ugly weeds. This is Labor Day weekend. The end of summer. It’s when weeds are at their ugliest. Sometimes I just wish for a big early freeze.  But as the days get cooler–soon, I hope–the growing slows down, and the weeds don’t seem so ominous and oppressive. I remind myself that weeding at its worst is still better than herbicides.

Reading and writing about creeping buttercups got me feeling a little attached to them. I guess I would miss them next spring if I were to eradicate them completely. So I will hope for a manageable few glossy blooms next spring and remember weeding early and often is one important aspect of fine gardening. The alternative is a week-long eradication project, which is not fine.

 

 

 

 

 

 

 

 

 

 

 

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