These pictures are flowers and leaves of Japanese Sweet Potato. Japanese Sweet Potato is also known as Dry Sweet Potato because the potato contains less water compared to American Sweet Potato. The fresh color of Japanese sweet Potato is creamy white. I think the taste of this sweet potato is greater than American Sweet Potato.
Anyway they bloom flowers in Autumn season when the day light time becomes shorter than night dark time. As you can see the flowers of this potato are beautiful. You can grow Japanese Sweet Potato easily. This plant doesn't select soil and most of the case you don't need to feed any fertilizer at all. If you feed fertilizer, usually you would get well grown foliage but small potatoes.