Yes, they multiply and if you are moving them around the yard say on a shovel or a glove, and a small piece of the corm falls off, you may find a new Oxalis in that spot in years to come but can't remember ever planting it there.

Does oxalis multiply?

Oxalis triangularis reproduce from bulbs. The University of Vermont Extension recommends dividing bulbs toward the end of plant dormancy, indicated by the appearance of new growth. ... The baby bulbs are ready for planting right away. Replant them just underneath the soil and keep the soil consistently moist.

Do oxalis plants spread?

Type of Plant

Oxalis is grown from small bulbs. It is relatively a slow growing perennial which spreads easily in a garden bed.