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The Monday Garden
Lesser Celandine: Marsh Menace

Issue No. 159 - April 10, 2005
by Sue Sweeney

  
Pure and simple, lesser celandine is not marsh marigold.

I've never seen a real marsh marigold, except in a pot. This endangered native treasure of the sunny spring wetland continues to allude me. I wish that I could say the same for the highly invasive look-a-like European cousin, the lesser celandine a/k/a fig buttercup a/k/a Ranunculus ficaria. Indeed, one of the reasons that I may never see a marsh marigold (Caltha palustris) is because the lesser celandine crowds out the marsh marigolds and other delicate native spring wildflowers like rue anemone, hepatica, bloodroot, Dutchman's breeches, trout lily, and Virginia bluebells that are trying to co-exist in the same environment. Lesser celandine is so bad that the US Geological Survey, not exactly an organization known for hyperbole, calls it a "travesty".

 
picture: lesser celandine along 3rd Street, Stamford CT, Spring 2004
 
Lesser celandine still seems to be a valued wildflower in England and Ireland, but in northern U.S. and southern Canada, it is an infestation. Lesser celandine's leaves emerge in the form of a basal rosette (circle of leaves close to the plant's base) in late winter; the flowers follow in early spring. As the flowers bloom, tiny bullets form along the stem. By June, the flowers are gone and the plants are dying back into the ground to escape summer heat and drought. The bulblets are left to add to the carpet, becoming underground food-storing tubers. Marsh marigolds, and most other self-respecting native forest/stream wildflowers, emerge a bit later which gives lesser celandine the edge in competing for resources.

While some of the bulblets get carried away by flooding to start new colonies, lesser celandine is primarily spread by human gardeners, including those who innocently dig up some of the pretty plant from along the road and take it home to ruin their lawns. Believe it or not, lesser celandine cultivars are still widely sold! Please don't buy them, and please tell the nursery that you wish that they would stop stocking invasive plants.

 
picture: lesser celandine having taken over a waste space next to a parking lot, 3rd Street, Stamford CT, Spring 2004
 
Both lesser celandine and marsh marigold are low-growing with shiny green, rounded leaves, and big, shiny buttercup flowers. There are subtle differences in the appearance but the main way to tell them apart is by behavior. If you come across an entire yard, stream-side or forest thickly carpeted with the stuff, it is lesser celandine. Marsh marigolds grow in mannerly clumps; it doesn't take over.
 
picture: lesser celandine annoying the skunk cabbage, along the Mill River at Scalzi Park, Stamford CT. Spring 2004
 
Unfortunately, by the time you have a major carpet of lesser celandine, you almost can't get rid of it. Small clumps can be hand pulled and persistent hand pulling can be successful but you're talking about years of dedicated stoop-labor. Note, though, that you have to get every last bit. If you leave any of the tubers or bulblets, they'll flourish in the ground that you disturbed when digging the main plant. Unless you come back, year after year, to dig out the progeny, the end result will be more plants than before the soil was disturbed.

Even more sadly, any of the more drastic eradication measures, such as sterilizing the ground with a black plastic cover (see Issue 110), are as likely to wipe out the plants that you're trying to save as well as the bad guy.

Some forest custodians have been reported to be trying a broad-leaf weed killer application before other spring treasurers emerge. This, though, raises all the problems and questions about use of pesticides; and there are many of us who believe that the cure is invariably worse for the planet then the original problem. There is no known biological control that won't also wipe out the good guys.

In case you come across a small clump of buttercup yellow-flowered something and are trying to determine whether it is one of the good guys, here are some of the more subtle differences between lesser celandine and marsh marigold:

--Lesser celandine generally has 8 petals (can be to up to 12) or is double-flowered; marsh marigold has 5 to 9 petals (actually sepals, if you're a botanist).
--Lesser celandine has kidney to heart shaped leaves; marsh marigold leaves are rounded to kidney shaped.
--Lesser celandine make bulblets along the stem and has an underground tuber; marsh marigold does not.
--Lesser celandine tends to grow a foot or less in height: marsh marigold can get to be 2 feet tall.
--Lesser celandine has been hybridized to include varieties with variegated leaves and double flowers

What can you do? Save some of the endangered wildflowers by planting them in your garden instead of the invasive ones. Of curse, never ever collect endangered plants from the wild and buy only from reputable dealers who grow their own stock from, hopefully organic seed.

 
picture: lesser celandine taking over a garden on Chester Street in Stamford CT April 2005
 
BTW: What is greater celandine, you ask. The real celandine (Chelidonium majus) is a biannual herb in the poppy family from Europe and Asian, historically used for medical purposes (but not generally proven to be effective and has raised questions about possible extreme side effects like liver damage). Celandine's naturalized in woodland areas in northern U.S. and southern Canada. It does co-exist with others, so it is not considered a particular threat to native flora (at least at this time).
 
picture: detail of lesser celandine, 3rd Street, Stamford CT, Spring 2004
  
From The Monday Garden. Copyright © by Sue Sweeney. Reproduced with permission. 

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