win the bug catching contest. Or you can buy with athlete's points from the poke dome.
You have to give it a sun stone.
you can evolve a gloom into a vileplume or a sunkern into a sunflora with a sun stone in PKMN SS versionGloom evolves with a Sun Stone into Bellosom in Pokemon SoulSilver.
You have to use the sun stone on sunkern at any level but it is hard to get a sun stone in soul silver.
you can buy one in the pokeathon dome for 3000 points.
You can have one by winning the Bug Catching Contest
Gloom will evolve into a Bellossom and Sunkern will evolve into a Sunflora.
Depending on what game your playing you can only receive one sun stone but in heartgold and soulsilver if you win the bug catching contest you can receive a sun stone and you can do this multiple times.
You'll need to give it a Leaf Stone to evolve it into Vileplume or use a Sun Stone to evolve it into Bellossum.
You cant catch bellosum so you have to catch a gloom and envolve it using a sun stone
The Sun Stone causes Gloom to evolve into Bellossom. It also causes Sunkern to evolve into Sunflora. You can either win it from first place at the Bug Catching contest, or the Pokeathlon dome.
you use it on some water type Pokemon to evolve them. example:pikachu+thunder stone example:polywhirl+water stone example:evee+fire stone example:Roselia+sun Stone example:murkrow+dusk stone a ever stone prevents your Pokemon from evolving
A Dusk Stone is an evolutionary stone that evolves Murkrow and Misdreavus.