My plants are in the ground -- do I dig them up when leaves turn yellow?

You can just leave the bulbs in the ground, and once the leaves dry out, place one hand at the base of the plant and press down to be sure not to pull the bulb out when you remove the dried out leaves. If a bulb uproots when you remove the dried out leaves, just re-plant it in the ground, pointy end facing up. You can trim off the dried out leaves close to the ground, as well. The most important thing about freesia bulbs, or any bulbs for that matter, is not to let them get too wet when they aren't in bloom. Otherwise, they will rot and get moldy. Bulbs always pop up in the spring, and with every year they spread and there will be more and more of them.