From Bulbapedia, the community-driven Pokémon encyclopedia.
The Sunflora Lodge (Japanese: ペンションキマワリ Pension Kimawari) is a location in Johto exclusive to the anime. It appeared in Moving Pictures and is located in between Ecruteak City and Olivine City.
It is most likely called this because Sophia and Marcello, the two who run the lodge, live here and take their anniversary photograph with hundreds of Sunflora every year. It was visited by Ash, Misty, Brock, and Todd while they were trying to defrost a Sunkern after an Articuno flew past.