Well, I think that one of the most important motifs are the flowers that are referred to at various stages of the story. It is important to consider the overall effect on the villagers that the drowned man creates. At the beginning of the tale we are given a rather bleak description of the village:
The village was made up on only twenty-odd wooden houses that had stone courtyards with no flowers and which were spread about on the end of a desertlike cape.
Everything confirms the desolate and drab nature of the village. Yet, by the end of the tale, as they plan and carry out Esteban's funeral, note how his appearance in their lives seems to have given them the impetus they need to realise that they can do something to change their rather hopeless situation, symbolised by the flowers they wish to plant:
But they also knew that everything would be different from then on... because they were going to paint their house fronts gay colours to make Esteban's memory eternal and they were going to break their backs digging for springs among the stones and planting flowers on the cliffs so that in future years at dawn the passengers on great liners would awaken, suffocated by the smell of gardens on the high seas...
The flowers thus represent perhaps the potential that the villagers within themselves find to change their situation and transform their village from rather a bleak, foreboding place to a place renowned for its beauty, vibrancy and colour. Of course, Marquez is gently poking fun at the villagers, and at all of us, and our need to have a hero to give us that catalyst - for that potential for self-transformation is within us all, Esteban or no Esteban.