I know for sure that spraying vinegar won't even make it feel ill. I hate it, too, but I think it will survive a nuclear holocaust.

Those roots, you know . . . they go a good 6-ft. down. I've heard of cases where it was "killed" with glyphosate, the property rototilled and re-graded, and sod layed-down ... and it came back.

Redefine it as a ground cover?

Jeri--six feet! Ugh! Nope Michael, no ground cover of oxalis for me!

I don't mind Oxalis so much when it is lush and green, but when it tries to choke my plants or starts looking dry and ugly, I get to pulling, and pulling and pulling...

Here's a quote that might not be the advice you were hoping for (sorry), but it made me smile and hope it will make you do the same:

I appreciate the misunderstanding I have had with Nature over my perennial border. I think it is a flower garden; she thinks it is a meadow lacking grass, and tries to correct the error.~Sara Bonnett Stein

And here is another:

Despite the gardener's best intentions, Nature will improvise. ~Michael P. Garofalo

"If you don't plant something, God will!" Ralph Moore.

There are seeds and bulbs of oxalis everywhere. The homeowner likely did knock the existing plants down, but once you disturb the soil, you unearth and expose bazillians (that's a WHOLE lot!) of existing seeds, just waiting for the right conditions to germinate.

Here isUC Davis' page for dealing with Oxalis and its relatives.

The common yellow oxalis we have here has tiny "bulbules" (sp?), which lurk 12 -18 inches under the ground. You can easily pull up the plants, of course, but those tiny bulb things stay under the soil, and up it comes again. I once had a gardener who decided to eradicate it from a flower bed which is about 12 feet long and 6 feet wide. He actually dug up the top 2 feet of soil, and sifted it by hand to get all of the tiny bulbs out. That worked for the first year, but by 2-3 years after he did that, back the oxalis came. So, being lazy, what I do is just admire it in the Spring, except where it is trying to smother other plants. Then just pull it out around those plants. By late Spring here it has died down, and I pretend it is gone. Of course, it comes up again the next Spring. It is one of our first blooming plants to bloom (starts Jan/Feb), so I just regard it as such and let it be mostly. One of my cats likes to eat it (we used to eat it as children - we called it "sour grass").

Jackie

I have the wild one and one of the hybrids with a lavender bloom. Nothing has worked, so I'm going to try to "solarize" them under black plastic to see if it will just cook the bulbletts. I have no idea if it will work or not, but I'm desperate. It seems like Florida sun should fry anything under black plastic. I've been fighting them for years.

Jackie, I had the word "sour grass" also as a child in central Florida (then a southern culture) many years ago.

The oxalis here doesn't go dormant in summer. The little bulbs are only a few inches deep. Still, it is a nuisance because it loves nestling up to the thorny base of rose bushes.