Sunday, July 2, 2017

Plant Story--Curly Dock, Internationally-Known Weed

What are those big leaves?

curly dock, Rumex crispus

They stand out in the grass or beside the fence.

It is curly dock, also called yellow dock and sour dock, Rumex crispusbuckwheat family, Polygonaceae. Curly dock came from Europe and is a worldwide weed.  I've seen it in

Oslo, Norway
curly dock, Rumex crispus, Oslo Norway

on Jeju Island, South Korea

curly dock, Rumex crispus, South Korea

in Lisbon, Portugal

curly dock, Rumex crispus, Lisbon, Portugal

Edmonton Alberta

curly dock, Rumex crispus, Edmonton, Alberta

and Loveland Colorado
curly dock, Rumex crispus, Loveland, Colorado

I could go on...curly dock is found all over the Northern Hemisphere. 

And probably all over the cooler parts of the Southern Hemisphere: this sighting was on the southern tip of South America, Ushuaia, Argentina.

                                       curly dock, Rumex crispus, Ushuaia, Argentina

There are at least 200 species of Rumex, called sorrels as well as docks. Sixty three species of Rumex are found in North America, some native, some from Eurasia. Curly dock is one of the biggest, with leaves that wave or curl and grow up to a foot long. It is native somewhere in Eurasia but came to North America soon after the Europeans.

No meaning is given for Rumex, it is simply the name the Romans called these plants. Botanists speculate that it is from the Latin rumo, meaning to suck, because the Romans allegedly sucked the leaves to alleviate thirst. The species epithet of curly dock, crispus, means curled, referring to the distinctive waving of the leaves (see that first set of photos). 

seeds of curly dock, Rumex crispus
Curly dock seed pods                                          
Curly dock is a perennial with a deep tap root. It may grow four feet high. The flowers are small, greenish or reddish, very inconspicuous. The seed pods, however, are easy to spot, standing above the plant in masses. Dark brown when ripe, there is one seed per small papery pod. My pictures looks like the plants with the red-brown seeds are dead, but they are not, they are dormant and will be back next year.
curly dock, Rumex crispus
Curly dock will grow in good soils, but tolerates poor ones, making it a hardy weed. In particular it grows well in wet and acid soils, so much so that a dense stand of curly dock indicates wet, acid conditions. 

curly dock, Rumex crispus
A low spot with many curly dock plants
As a perennial, you can cut off the top to remove it, but if you don't get virtually all of the roots, it will regrow. They clump rather than form large clones, however.

One other reason curly dock is a tough weed is that the seeds can last a long time in the soil. We have few studies of seed longevity, because long-lived seeds outlast the careers of scientists. Curly dock was one of the seeds in Professor Beal's famous study of seed survival at Michigan State University. Begun in 1890 and still running, bottles with seeds were set in the ground and after various intervals, dug up and planted to see if the seeds were still alive. (Beal's experiment) The curly dock seeds came up in all the planting experiments up to 80 years, but not at or after 90 years. Eighty years is a long time that the seeds can lie in the soil alive and waiting for favorable conditions: the property might well have five different owners in that period, before one is surprised to see dock in her garden.  


Currently, curly dock is reported from every state, province and territory on the USDA's plant distribution map except Arctic Canada (map). In Arkansas is it a noxious weed, which means the state is actively trying to eradicate it, and Iowa mentions it as a minor noxious weed, that is, they don't want it but are not spending money getting rid of it. But all across the rest of the continent, it is just a European plant found in waste areas and disturbed sites. It isn't spiny or toxic or a vine that makes harvesting crops difficult. 

That's faint praise...I will talk about its folklore and uses (it is tasty!) next post. 

For now: notice curly dock, if you are not in the tropics, it almost certainly grows near you. 

Comments and corrections welcome.

Jones, P. 1994. Just weeds. History, myths and uses. Chapters Publishers and Booksellers, Shelburne, Vermont. 
Minnesota Curly dock link 
Return to Nature Curly dock, Rumex crispus. link 
W.J.Beal Botanical Garden, East Lansing, MI. Research and teaching. link  Summary of Beal's experiment. 

Kathy Keeler, A Wandering Botanist

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