This is the draincover for Nakayama Town, now incorporated into Daisen Town, on the southern slope of Mount Daisen in Tottori Prefecture.
The plant depicted is Hamanasu (lit. Shore pear), Rosa Rugosa , a Japanese Rose native to east Asia. The coast in Nakayama is the southernmost point of the plants habitat in Japan.
The Japan Times this week has an excellent short article on the history of decorative drain covers in Japan. Access it here.
I've also come across a website (in Japanese only) that has a map of draincovers in Japan. They don't have all of them though. Access it here