I'd say when ever ya feel up to doing it. Seems they have a slower period about now here in New Orleans.... the heat of summer maybe? However you couldn't kill the little darlings even if you wanted too ;o) Ask any local gardener about getting the common green leafed pink flowered form out of their garden beds. Can't be done ;o)
Mike

I was just told by someone who collects oxalis that you need to divide them every year to keep the bulb from getting tiny and the plant spindly. Sorry but I don't know when. I'd think about anytime since I just planted seeds and they were blooming within less than 2 weeks. No kidding!

Nancy

Bigred- this is an old thread but I had success dividing Oxalis by letting them go dry in the late fall so they will go dormant. After the foliage had dried out and died down, the little tubers are completely dormant and can be dug and divided. I got enough out of my one pot to make 5 or more new pots. Has anyone tried growing these outside? They are supposed to be hardy but I'm wondering... Other Oxalis do seem to overwinter like Iron Cross.

Yes i have grown them outside in container with other plant and it its beautiful i will post a picture uner purple leaf oxalis I also have planted them in the ground they also do very will the best time to divide is fall when it finish flowering cut it down and it easyer Anna

I've grown them outside in Z6; I let them spread over the summer and then harvest after the first frost (they're only hardy down to Z7, and that's pushing it).

I started with one plant 10 years ago and now have dozens of pots and planters and have given as many away. Divide anytime you want. If you keep them growing inside, they won't go dormant unless you stop watering them. They're so prolific that after a year, three or four tubers almost fill an entire 6" pot. The stems are fragile, so expect to lose some leaves when you divide; but don't worry, more will start popping up a week or so later.

When dividing, I like to plant the tuber with just 1/4" of soil on top; they seem to like at least part of the plant near the soil surface.

I grow them outside and inside.Dug some out and found a big translucent addition to the corm complete with roots.
Any idea what this is ?