Curly dock is a native to Europe, Asia and northern Africa, but it has been introduced and naturalized throughout much of the rest of the world (see: Germplasm Resources Information Network (GRIN) on Rumex crispus and Pacific Islands Ecosystems at Risk (PIER) for the plant). One of its noteworthy qualities is its ability to produce an estimated 100 to over 60 000 seeds per individual plant per year (photographs). If that weren’t enough, the seeds can persist in the soil for many years, have a high germination rate and, once seedlings, have a high chance to survive to adulthood.
The second image shows an all-too-familiar scene in early August of 2005 in the southeastern corner of Manitoba. Heavy rainfall through spring and early summer prevented many farmers from being able to access the fields, much less sow seed. As a result, the fallow fields instead grew “crops” of water-tolerant plants, including Rumex crispus (curly dock) (the tall reddish-brown plants) and Hordeum jubatum (foxtail barley), the tufted clumps. As an aside, everytime I saw distant clumps of Hordeum, I was reminded of flocks of sheep. I’m told I have an active imagination.
For more on this resilient plant, see: Zaller, JG. 2004. Ecology and non-chemical control of Rumex crispus and R. obtusifolius (Polygonaceae): a review. Weed Research. 44(6):414-432.