It is unlikely your bulbs will rot IF your soil is well drained, and assuming you don't over water. This, of course, depends on what kind of bulbs you are growing too. I live in Zone 8A. I use a wide variety of bulbs throughout my garden and have never had this problem. But yes, if they rot, they will simply disappear. You know the bulbs are still underground because they put up new growth each year at approximately the same time. For instance, daffodils usually begin to appear around here in late November or early December. As time goes by, you will get a feel for when each type will appear and disappear.

great, thanks!