If they did exist, what happened to the gardens? There is a report that they were destroyed by an earthquake in the second century B.C.. If so, the jumbled remains, mostly made of mud-brick, probably slowly eroded away with the infrequent rains.
Whatever the fate of the gardens were, we can only wonder if Queen Amyitis was happy with her fantastic present, or if she continued to pine for the green mountains of her distant homeland.