Answer: Healthy potato plants will bloom during the summer. Here is a picture of them courtesy of the World Bank web site:
The flowers are akin to those on tomatoes or peppers because the plants are related. They would appear sometime between 30 and 70 days after the shoots emerge; the difference depends on the variety you are growing, when they were planted and how the weather has been. After blooming the tops will begin to die back indicating that the potatoes under ground have reached full size, so it is possible you missed the flowers and what you are seeing is normal.
Q&A Library Searching Tips