Try the National Park Bug Contest and win usually you get a random evolve stone
Catch a Gloom, then give it a Sunstone.
You find sun stone underground!
you just need a gloom and a sunstone use the sunstone on your gloom and walla you have a bellosom
There is no sunstone in Pokemon red it onnly appears in later games.
Cottonee -> (Sunstone) Whimsicott
Bellossom can be obtained by evolving a gloom with a sunstone.
this Pokemon will evolve if sunstone is given to hold: oddish (lvl 21) -> gloom (sunstone) -> belossom sunkern (sunstone) -> sunflora
Win 1st place in the bug catching contest.
you can find it on ground or using dowsing machine
in the Pokemon games, you give a sunstone to an eligible Pokemon and they will evolve. for example, Gloom will evolve into Bellossom when given a sunstone and Sunkern will evolve into Sunflora when given a sunstone.
in mossdeep city and some wild Pokemon have it ,too probally wild oddish and gloom
There are only 2 things a sunstone does. it evolves gloom to bellosom and sunkern to sunflora.