Sheep Sorrel, Sour Weed, Red Sorrel
Synonyms of Rumex acetosella: Acetosa acetosella (L.) Mill., Acetosa hastata Moench, Acetosa repens Gray, Acetosa sterilis Mill., Acetosella multifida subsp. tenuifolia (Wallr.) Kubát, Acetosella multifida subsp. vulgaris (Fourr.) Kubát, Acetosella vulgaris (W.D.J.Koch) Fourr., Acetosella vulgaris subsp. tenuifolia (Wallr.) P.D.Sell, Lapathum acetosella (L.) Scop., Lapathum arvense Lam., Pauladolfia acetosella (L.) Börner, Rumex acetosella var. tenuifolius Wallr., Rumex arvensis Dulac, Rumex falcarius Willd. ex Ledeb., Rumex fascilobus Klokov, Rumex tenuifolius (Wallr.) Á.Löve
Rumex acetosella L. is the correct and accepted scientific name for this species of Rumex. The genus and species were named and described as such by Carl von Linnaeus in the first edition of the first volume of Species Plantarum in 1753.
Accepted infraspecific names include Rumex acetosella subsp. acetoselloides (Balansa) Den Nijs, Rumex acetosella subsp. arenicola Y.Mäkinen ex Elven, and Rumex acetosella subsp. pyrenaicus (Pourr. ex Lapeyr.) Akeroyd. I think only the last one is found in the United States (in New York).
Plants of the World Online lists 195 species in the Rumex genus (as of 4-18-20 when I am updating this page. Rumex is a member of the Polygonaceae Family with a total of 55 genera. Those numbers could change periodically as updates are made.
The above distribution map for Rumex acetosella is from Plants of the World Online. Areas in green are where the species is native and purple where it has been introduced. The map for North America on the USDA Plants Database is similar.
There are several links at the bottom of the page for further reading and help with a positive ID.
I found this good-sized colony of Rumex acetosella, or Sheep Sorrel, in the yard while I was mowing. I am sure it has been here for years but somehow I just paid attention. Now, I didn’t know what it was at first and probably before I just thought it was smartweed because at a glance that’s what it looked like. But, since I ave been doing a lot more wildflower ID, especially with the several Persicaria species in 2019, I knew this wasn’t any Persicaria. Besides, in April they are just beginning to come up. I went around most of the colony of whatever it was so I could take photos later and properly make an ID.
Rumex acetosella is a perennial plant that spreads by seed and long creeping rhizomes and is a native of Eurasia and the British Isles.
So, after taking a lot of photos I uploaded the first one on iNaturalist, entered my location, and within seconds I had the ID of this colony. It is just weird this plant is not growing anywhere else on the farm except this one location in the yard.
Stems are upright or ascending and grow up to 18” tall and often branch out at the base. Each branch terminates with an inflorescence. Stems are ridged and hairless (glabrous) with a papery sheath (ocrea) at the nodes. Stems seem to be green at the bottom but reddish at the top and kind of streaked in the middle.
The interesting leaves can be thin to slightly succulent, narrowly ovate, lanceolate-elliptic, lanceolate (lance-shaped), or oblong-obovate, usually with a pair of triangular spreading basal lobes.
The basal leaves are somewhat larger and form a rosette but I need to take a closer look or maybe find plants somewhere I haven’t mowed. I didn’t notice any rosettes of larger leaves on my first observation of this colony BUT after looking at photos on Missouri Plants I think I have noticed them in other places. So many plants look a lot alike in the spring before they start flowering. Since I mowed this colony a few times I could have damaged the basal leaves.
Flowers are born on long inflorescences with several racemes. It is like the entire upper half or more of the plant is an inflorescence. Flowers are staminate (having stamens but no pistols). None of the flowers were open when I took photos. Flowers are dioecious meaning plants produce all male or all female flowers and they are wind-pollinated. You can see in the above photo the leaves have cut by the mower.
The above photo shows the papery sheaths on the stems where leaves and branches emerge. They become nearly translucent and raggy with age. Stems have ridges that seem to be red-tinged in the middle of the plant and more reddish at the top.
The flowers are hairless I think, or mainly so. What appears to be hair in this photo are likely grass clippings.
The above photo is a good example of an “obovate-lanceolate” type of a leaf. Even though the upper leaves are pretty small, you can see they are lance-shaped, broader in the center, taper to a point, and have interesting spreading basal lobed. Information says the basal lobes are triangular. Hmmm… Interesting how you can see a raised vein on each side of the midrib from the upper surface of the leaf otherwise it is very smooth. Even the leaf margins are smooth. This leaf was fairly thick and fleshy for its size.
The underside of the leaf I was photographing shows a very prominent midrib and a few veins going toward the margins. The undersurface appears kind of powdery but I can’t remember the scientific name. Perhaps finely pubescent…
OH, the leaves have long petioles…
Plants produce oxalic acid which gives it a sour flavor and tannins which contribute to its bitterness. It is used in cooking and in salads but should be used in moderation. The species name acetosella means “acid salts”. Handling the plant can also cause dermatitis in some people.
Rumex acetosella is a problem species that grows in a variety of conditions but prefers acidic soil. It can become quite invasive. Information suggests the species contributes to hay fever due to its windborne pollen.
Normally, I allow plants to naturalize in certain areas, but perhaps this one I should think about eradicating. Information suggests it could be a problem and may be hard to get rid of.
I am going to keep my eye out for some larger rosettes and maybe I can find this plant elsewhere on the farm (ALTHOUGH, I am not sure I want to).
I have enjoyed photographing and learning about the many wildflowers growing on the farm and other areas. My farm is in Windsor, Missouri in Pettis County (Henry County is across the street and Benton and Johnson aren’t far away). I have grown over 500 different plants and most have pages listed on the right side of the blog. I am not an expert, botanist, or horticulturalist. I just like growing, photographing and writing about my experience. I rely on several websites for ID and a horticulturalist I contact if I cannot figure them out. Wildflowers can be somewhat variable from location to location, so sometimes it gets a bit confusing. If you see I have made an error, please let me know so I can correct what I have written.
I hope you found this page useful and be sure to check the links below for more information. They were written by experts and provide much more information. Some sites may not be up-to-date but they are always a work in progress. If you can, I would appreciate it if you would click on the “Like” below and leave a comment. It helps us bloggers stay motivated. You can also send an email to me at email@example.com. I would enjoy hearing from you especially if you notice something is a bit whacky
NOTE: Plants of the World Online is the most up-to-date database. It is very hard for some to keep with name changes these days so you may find a few discrepancies between the websites. Just be patient. Hopefully, someday they will be in harmony. 🙂