I grow O. regnellii in pots of evenly moist, organically enriched soil on the porch, where they get some early-morning sun but are in bright, indirect light for most of the day. Yellowing foliage is a sign of too much moisture. An occasional application of a diluted balanced fertilizer is beneficial. Remove spent foliage and flowers. It prefers the cooler months of the year.
Some gardeners complain that oxalis is invasive, but so far, it's well-behaved in our garden.
Every few years, I see O. deppei, a k a rosette oxalis or lucky clover, which has four bright-green leaflets joined by a large purplish spot. The tiny pinkish-rose flowers rest at the end of long, slender stalks. This, too, is suitable for growing in a container or the garden. The problem is, it's difficult to locate. It is not aggressive in beds and works in pots on the patio.