In Viridian city. You need to get all the other 15 badges first and then go talk to Blue on Cinnibar island/city.
Chat with our AI personalities
mt silver or 16 badges safari zone mountain area
Professor Oak gives you it after you get 16 badges
You have to beat all 16 gyms.
Chikorita evolves into Bayleef at level 16.
Chikorita - Bayleef lvl 16 Bayleef - Meganium lvl 32