I just pulled a bunch yesterday and it's much easier than you think. The stems radiate out from the centre. I used my trowel to gather them all up and then pulled them out.

I wish I had some - just love them in lawns. Hopefully I can find some seeds.

In the past, I worked at country clubs and was culturally adjusted to dislike weeds in turf.

Then I decided that there was nothing wrong with other plants in lawns. In fact, lawns with flowers may look even better.

Thank you all!
I'm surprised that anybody likes the oxalis in the lawn, but that's great! I won't worry about it. Occasionally I have oxalis in the flower beds and under good conditions they can grow several inches tall hidden inbetween flowers. The stuff in the lawn looks the same but is much, much smaller. The cover on the septic tank has nothing else growing on it but 'oxalis'. My lawn is 3/4 acre large so hand weeding is not an option.
Leena1947

One more thing I like about it, is how it can flourish with less water than grass.

For those folks who want less of it, one thing comes to mind, at least concerning one Oxalis - I was taught in college that germination is more prevalent when direct sunlight can get to the seeds.

That means that mulching-over seeds in beds discourages Oxalis, compared to how mulch can encourage other weeds with the cover.

Applying this to lawns, I'd guess that Oxalis will germinate more freely in short lawns, and less in taller lawns where grass blades shade the soil surface more.

I can't vouch for this 100%, but 25 years of working with lawns and shrub beds makes me think there is something sensible about the theory.

I have the oxalis coming up in beds and in pots but don't notice it in the lawn. I leave it alone in beds and seem to have several varieties. One has very dark foliage and gets taller. I grow the dark Oxalis triangularis aka regnelli
with the triangular leaves and pink flowers in the house, so I kind of like the dark one.

It is very soft and pretty filling a pot under the plant, too. I grow some Oxalis for outdoors, like Oxalis deppei Iron Cross, and Oxalis adenophylla, with lovely crinkly blue-green leaves and pink flowers.

I don't mind the white clover in the lawn but hate the yellow in my flower beds. It comes up in the middle of my groundcovers and I can't get rid of it. It also comes up through sedums and sempervivums and heaths and heathers and ornamental grasses.

Yellow sweet clover is quite a pest in my yard too, buyorsell. It has very tough invasive roots and spreads rampantly. It's all over my lawn, too. I wish I could tell you what to do about it. It also loves to mass roots under my newspaper mulches. Arggh. I guess trying to keep it from going to seed and trying to get the roots is all I can do.

I loathe Oxalis. Especially when it starts shooting its sharp little seeds at you. It kind of hurts, and they get all over your clothes. Nasty.

I just got back instead after spraying the Oxalis in my yard with BurnOut II from St. Gabriel Laboratories. It works great on Oxalis! Those little weeds turned brown within half an hour.

Does anyone know where the best place to buy this stuff is in the Seattle area? I paid $60 (eek) for a gallon of the concentrate at City People's last fall. The St. Gabriel website sells it for $45 plus $15 shipping, so that would be a wash.

I like it because it's dog- and people-safe, made from clove oil, lemon juice, vinegar, and other natural ingredients. Plus, it smells great. But $60 ($66 after tax) is a lot of money.

My neighbor has little yellow flowers in her lawn, that are definitely NOT oxalis. I know what that looks like. Does anyone know what it might be? She doesn't know. It's very pretty. The flowers are smaller than oxalis (maybe little daisy shapes?) . It seems to grow in a low damp part of her yard in full sun. It's probably something horribly invasive, but it's very pretty.

Thanks again for all the responses!
The yellow flowers in my lawn look the same as the oxalis that comes up in flower beds but the leaves are green, clover-like, and the flower itself is only half the size if not smaller. Really tiny. The lawn gets full sun most of the day. I have been mowing the lawn to 2 3/4 inches in the hopes that the grass blades would prevent germination of more of the pest!
Hemnancy, sounds like you have the same problem as I do.
leena1947

I hate those nasty shooting seeds too!

The plant in my yard that shoots seeds, my sister calls it Artillery weed, has a small rosette of basal leaves and then a flower stalk with tiny white flowers. Oxalis makes a seed pod that looks like a tiny banana, in fact I liked to eat them when I was a kid as they tasted acidic. I'm not aware of them ever shooting seeds at me. Perhaps we're not all talking about the same plant. Oxalis looks like a three-leaved clover. There are photos in the Paghat link in my previous post. I spend a lot of time in early spring trying to get all the "artillery weed" before it starts shooting seeds, I hate it too. But I like Oxalis a lot.

If you know the ingredients for the Burn Out II, maybe you could try to mix up something similar. Azure Standard has clove oil. I've heard of using vinegar and a little orange oil cleaner mixed in to kill weeds.

Misslemonverbena - it might be buttercup. It is pretty, but it is a horrible thug.

I think I might have found the weed I am trying to ID: oxalis corniculata. I found literature that says it is a real pest in the lawns. It has a creeping habit and the picture looked exactly like my weed: green cloverlike leaves and a tiny small yellow flower, about 1/8" in diameter.
Leena1947

There is a native Oxalis, Oxalis oregona that we called "Sour Grass" as a kid because when you eat it, it tastes sour.

That is not the weeds we are talking about. I do have it in my garden but on purpose.

I have three different Oxalises that are weeds. A burgundy leaved one with yellow flowers, a green leaved one with yellow flowers that shoots seeds, both small leaves and small flowers and then the bigger leaved one with white flowers in the lawn.

I also have the little weed that shoots seeds that hemnancy describes. It pulls up a lot easier though.

I looked at the Wikipedia listing for O. corniculata and apparently it can shoot seeds. I haven't been at the right place at the right time, apparently... There is also an upright species mentioned, O. stricta, also common in nursery pots, but I'm wondering if the other plants mentioned are in the clover family instead, which the Oxalis family resembles. My pesky yellow clover is Trifolium aureum. I would really like to get rid of it. The seed pods on it become sharp when ripe. White clover is beneficial, since it fixes nitrogen and can feed lawns, but attracts bees if that is a problem for some. I encourage it in my lawn and try not to mow the seedheads until they ripen then spread them around some.

Here is a link that might be useful: White clover

Clovers and oxalis have similar leaves but very different flowers. The clovers have ball shaped flowers, while the oxalis have a more 'normal' shaped flower. Ranunculus also creeps through damp lawns and has yellow circular flowers, but much larger than oxalis usually. Then there's lotus, which also likes lawns, but its yellow flowers are very oddly shaped with points like bird's beaks. Also bur-clover creeps through lawns and has yellow flowers, tiny, kind of ball shaped like clovers, but it develops horrible spiny seed pods that cling to your socks and impale themselves into your feet. Real clovers don't make those spiny seed pods. Sweet clovers are very tall things, I don't think they'd grow in a lawn but I do see them in pastures and meadows that don't get mowed like a lawn does. I think the sweet clovers are related to alfalfa.

I realize this is an old thread, but I'll respond nevertheless. The plant you're all referring to is likely Lesser celandine (Ranunculus ficaria). In central Maryland, it appears in early spring -- before almost anything else. It is considered an invasive in this area. It forms small bubils at it's base. The leaves die back shortly after blooming, but the plant lives as a bubil for the rest of the year. The best way to control/eradicate it is to simply dig it up. The roots are shallow and separate easily from the soil. Just make sure you dispose of the bulbils properly or they will easily regrow. I throw mine in with the compost. I usually leave a few because they are quite pretty when the are in bloom. However, left unchecked they can easily crowd out everything else in your garden.