Curly Dock and Broadleaf Dock

2017 March 18

These plants were growing in the ditch beside our road, and were photographed on July 5, 2016. At the time I took the pictures, I thought they were both the same species, but I’ve since found that they are different (but closely related) plants.

The first one is Curly Dock, Rumex crispus. This is a fairly tall plant, with this specimen standing something over three feet tall.

Curly dock is widespread in Michigan, and has fairly distinctive long, narrow leaves with wavy or “curly” edges.


When I took these pictures, the curly dock had finished blooming and was in the process of setting seeds, which are a main seed surrounded by a flat “wing” that helps them spread by blowing in the wind.


The second one is Broadleaf Dock, Rumex obtusifolius. It is similar to Curly Dock aside from having, well, broader leaves (and also being a bit shorter, I think).


The Broadleaf Dock evidently blooms a bit later than Curly Dock, as this one still had blossoms and not ripening seeds.

Anyway, both of these plants are non-native species that came over from Europe, and both are occasionally considered to be invasive weeds. They have been spread around the world by having their seeds contaminating crop seeds, and they do particularly well in disturbed soil. They are both somewhat edible as long as you don’t overdo it, but they contain oxalic acid, which is tart-flavored and kind of toxic[1].

They also have a reputation for medicinal use, mainly for skin diseases or as a mild laxative. This isn’t because of the oxalic acid, but rather because of the anthroquinones that they also contain[2].

[1] Oxalic acid is not a complicated toxin, it isn’t cumulative or carcinogenic or likely to cause subtle and mysterious symptoms. It causes straight-up physical damage to tissues. It immediately damages lungs and mucous membranes if inhaled or swallowed, and causes joint pain and kidney failure by precipitation of calcium oxalate crystals (which makes kidney stones). The potentially lethal dose is around 15-30 grams for an adult human, so a little bit won’t kill you, but sore joints and kidney stones are no picnic, so don’t get carried away.

[2] When I was a kid, I remember reading somewhere that dock juice was supposed to be good for bee and wasp stings (rub it on the sting and it would feel better). But now that I’ve been stung a few hundred times by many things, I think that most sting remedies are just to give you something to do while the pain fades naturally. When I get stung by a bee, it hurts intensely for about 5 minutes, and then fades gradually over the next 10 or so, which is about the amount of time it would take to find a dock plant, pull off a stem, and squeeze out the juice.

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