The myth goes something like this: bees will not forage within a 25-foot radius of their hive because that is the “cleansing area”–or restroom, if you will. This is nonsense.
The rumor probably arose when beekeepers watched their charges fly right past flowers within inches of the hive only to alight on something in the distance. Remember that honey bees practice floral fidelity, meaning they want all the pollen collected on one foraging trip to be of the same species. If there aren’t enough flowers of one species near the hive, the bees will fly on to a place where there are many similar flowers.
There are other reasons, too, that may cause the bees to ignore your carefully tended near-hive plants. Something else may be sweeter, more attractive, or fresher than those plants. Also, plants have nectar flows during different parts of the day. Buckwheat, for example, only secretes nectar in the mornings, so bees ignore it in the afternoon.
When all conditions are right, your bees will happily forage within walking distance of their front door. So if your hive sits in a vast field of clover, and that clover is freshly bloomed and secreting nectar, the bees will collect it.
Related to this argument is the fact that bees don’t necessarily defecate within 25 feet of a hive. One look at my truck, which in not anywhere near a hive, illustrates the point. It is polka-dotted yellow with bee poop about eight months of the year.