You Can't. Beat The Elite Four In Pokemon Emerald And There Will Be A New Area In The Safari Zone And There You Found Sunkern. Evolve Sunkern With The Sun Stone And You Have Sunflora!!!
Sunflora is a Grass type pokemon.
Sunflora is uncatchable in firered to get one either get a sunflora from Pokemon colosseum or Pokemon emerald.
It'll only make 2 species of Pokemon evolve: Sunkern into Sunflora, and Gloom into Bellossom.
Unfortunately you can't get sunflora in firered the only way to get is either from Pokemon emerald or Pokemon colosseum.
Gloom can evolve to Bellosom with sun stone....
sunflora
Sunflora is #192 in the national pokedex, and it is a Grass type Pokemon.
Sunkern evolves into Sunflora with the use of a Sun Stone.
Sunkern, the Seed Pokemon evolves into Sunflora, the Sun Pokemon. Both Pokemon are plant type pokemon.
sunkern
Sunkern evolves into Sunflora with sun stone. So you should seek for Sunkern.
If you want Sunflora you have get Sunkern, once you have Sunkern, then add the Sun Stone.