Oxalis stricta (Yellow Wood Sorrel)
|Also known as:||Common Yellow Oxalis|
|Family:||Oxalidaceae (Wood Sorrel)|
|Habitat:||part shade, shade, sun; fields, woods, lawns, disturbed sites|
|Bloom season:||June - October|
|Plant height:||6 to 20 inches|
|Wetland Indicator Status:||GP: FACU MW: FACU NCNE: FACU|
|MN county distribution (click map to enlarge):|
|National distribution (click map to enlarge):|
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Branched cluster of 2 to 7 blossoms on a long slender stalk up to 3 inches long emerging from the upper leaf axils. Flowers are yellow, 3/8 to ½ inch across, with 5 oblong, rounded petals and 5 lance-elliptic sepals about ¾ the length of the petals. The sepals can be smooth or variously covered in spreading hairs. Flower stalks are ½ inch or less in length, can be mostly smooth, or with a few scattered hairs pressed close to the stalk (appressed), or densely hairy with spreading hairs.
Leaves and stems:
Leaves are alternate or in whorls with long slender stalks, palmately compound in threes, ½ to 1¼ inch across, usually green but sometimes dark reddish purple. The heart-shaped leaflets look clover-like and fold up at night and on cloudy days. Leaflets are toothless, surfaces are smooth except for scattered appressed hairs on the lower mid vein and along the leaflet edges.
Stems, branches and leaf stalks are variously hairy, from mostly smooth to densely covered with fine, spreading glass-like hairs as well as scattered, shorter, appressed and opaque hairs, but becoming less hairy with age. Many of the spreading hairs are sectioned, divided by lateral membranes (septate). Multiple stems from the base are erect to spreading and much branched in the upper plant. Branches of spreading stems often grow more prostrate giving the appearance of a creeping stem but they do not root along the nodes.
The fruit is a green, erect, banana shaped capsule 3/8 to ¾ inch long, with 5 angled sides and the 5 sepals spreading at the base. A typical plant will have 3 to 5 capsules in a cluster, on erect to ascending stalks. Like the stem it has varying amounts of spreading, glass-like, septate hairs and a few scattered, shorter appressed hairs. The capsule stays green when ripe and the seeds are forcefully ejected when the capsule splits open.
The seeds are just over 1 millimeter long, uniformly brown, oval, flattened on two sides with transverse ridges across the surface.
Largely considered a weedy native, this and Southern Wood Sorrel (Oxalis dillenii) can be difficult to discern without a hand lens, or better yet a microscope using mature specimens. The characteristics to look for in Oxalis stricta are: the spreading glass-like hairs, the branching clusters with up to 7 flower buds and fruiting with up to 5 erect capsules on mostly upright stalks. The ridges on the seed are brown like the rest of the seed. O. dillenii typically has all appressed hairs, only 2 flowers in a cluster, 2 capsules on bent stalks, and white ridges on the seeds. Another very similar species is O. corniculata, a non-native that is low-growing and creeping, rooting at most nodes, with all brown seeds. O. corniculata has not yet been recorded in Minnesota but is present in neighboring states. Also as an observation, O stricta is more likely to be found along lawn and garden margins where they do not get frequent mowing and are often in part to full shade. O. dillenii is the predominant species in mowed areas in full sun and branches profusely from the base due to repeated cuttings.
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- Yellow Wood Sorrel plant
- Yellow Wood Sorrel with reddish purple leaves
- Yellow Wood Sorrel in disturbed habitat
- Yellow Wood Sorrel at a woodland edge
- close up of septate hairs
Photos courtesy Peter M. Dziuk taken in Ramsey County.
Have you seen this plant in Minnesota, or have any other comments about it?
on: 2013-07-09 15:30:09
Found this plant,I think, in my yard. I read somewhere this is only common as violet in norther Minnesota.
on: 2013-07-29 13:19:10
We are sure we have this plant growing in our flower gardens near the house. It seems to come up everywhere we have a bird feeder. First in the front of the house and then on the side only after we relocated our bird feeder that contains wild bird mix bought at our local feed supply store. The plants are in clumps and have yellow flowers and there are a lot of them. Once we removed the bird feeder permanently they are not recurring.
on: 2015-10-19 10:59:01
This has grown all summer in the flower bed near my house. I let it grow after I saw the flowers come out, and thought it was a nice touch. I noticed that it grows in the flower bed near the bird feeder, but not so much in the one away from the bird feeder. Interesting.
on: 2016-06-20 08:43:19
We have both purple-leaved and green-leaved.
on: 2016-07-21 11:27:30
This green-leaved sorrel is constantly overtaking my raingarden, lawn, flower beds, and woodland edge. It tries to compete with everything - lupine, harebells, hosta, aster, butterflyweed, etc. The lawn gets mowed once a week but the sorrel just grows as it pleases wherever it wants. I took a class in edible plants at the Dodge Nature Center several years ago and the green capsules are edible - you can add them to salads. The good news is that the capsules are really tasty and tangy!
on: 2017-06-18 14:34:23
Lots of it growing in my garden beds. I've always pulled them out before, but after rummaging around online, I've decided to let them go and see what happens. My mom called it "sweet clover" which is a bit of a misnomer as the leaves are actually rather tart - but fun to eat!
on: 2018-06-03 19:58:52
This plant grows in the garden near hostas and other plants. Quite persistent and fast growing. Tart lemony flavor (I chewed a couple leaves) that I read can be used in salads and for cooking to add flavor to fish.
on: 2018-07-14 09:35:45
I've been chopping this down for years. Decided to just let it go, and found need love it. Will probably let it thrive from here on out--consider it part of a pollinators garden.
on: 2019-06-02 16:29:57
You mention that Oxalis corniculata has not yet been recorded from Minnesota. I think I may have Oxalis corniculata in my lawn. The leaves are reddish-purple with appressed hairs along the edges and also along the stems. It has been in my lawn since I moved here in 1970.
on: 2019-07-19 08:15:46
A wonderful addition to a salad, for its slightly sour taste.
on: 2020-05-16 10:41:59
I have a lot of these sorrels growing in my yard, both the purple-leaved and regular kind. It is edible and I've used it in soups, too much oxalic acid isn't good is what I've heard.
on: 2020-06-13 18:26:13
Both the green and purple variety of wood sorrel grow wild around here, frankly weedy. Ever since eating a sorrel salad in a french restaurant we have added some sorrel leaves to any kind of greens we eat. The name sorrel is derived from sour, a taste due to the oxalic acid in the plant. As a MD I am familiar with calcium oxalate kidney stones but you can't consume enough sorrel to cause this problem.
on: 2021-07-26 21:12:10
I have quite a bit of this growing in a patch in the backyard. So much, I almost wonder if I planted it. Does it attract specific pollinators?
on: 2021-07-28 18:56:26
Luciearl, I don't think it attracts anything specific, but I have abundant sorrel in my gardens and do see bumblebees visiting them.
on: 2021-08-03 14:01:29
My front yard is covered with this stuff. Weed Killer doesn't faze it. Any tip for removing?
on: 2021-08-03 18:16:35
William, it pulls out very easily, but it can create copious amounts of seed so you could see it for years to come. I have tons in parts of my garden and just pull out the excess periodically. I have found that it readily fills in empty spaces but doesn't really compete much with some other ground covers, such as wild strawberry or ginger.
on: 2022-06-19 11:37:16
I think this is what I have growing in my yard, and not Oxalis dillenii. It is growing in spots that are mostly shaded. I have quite a lot of it, so I pull most of it, but leave it on the section of boulevard that I haven't landscaped, yet. I realize this is probably why I have to pull so much from my landscaped section, but I do think it's rather pretty.
on: 2022-09-24 13:11:37
We have sparse populations of the green variety here. I have eaten small amounts of this since childhood in KS. Still enjoy it when I find it, especially the small fruits.