It evolves grass type pokemon..... Just like in EVERY OTHER GAME....
i think it is a leaf stone
You have to buy it with athlete points in the pokelathon
He evolves via leaf stone
you can find a leaf stone in viridian forest in kanto in heartgold
try using a leaf stone
Fire Stone Water Stone Thunderstone Leaf Stone Dusk Stone Sun Stone Moon Stone Dawn Stone
I believe it is something like a shiny Pokemon or shiny leaf stone. Getting a shiny Pokemon takes LOTS of luck, and a shiny leaf stone I think you find in patches of grass outside of Violet City in HeartGold. Hope this answers your question
It will only evolve through the use of a leaf stone.
leaf stone,lvl up with high freandship
you can get one in viridian forest that's all I know.
Gloom -> Vileplume Weepinbell -> Victreebell Exegcute -> Exeggutor
You will either have to evolve a Weepinbell with a leaf stone or trade it from somebody