Oddish evolves into Gloom at level 21.
Oddish evolves at level 21 in HeartGold.
Wooper will evolve at Level 20.
LEVEL 25
you have to trade
Level 21
Oddish evolves at level 21 in HeartGold.
Snorlax does not evolve. In gold, it is a non-evolutionary pokemon.
Unowns do not evolve.
Bulbasaur, Ivysaur, Venusaur, Butterfree, Oddish, Gloom, Vileplume, Venonat, Venomoth, Bellsprout, Weepinbell, Victreebel, Exeggcute, Tangela, Hoppip, Skiploom, Jumpluff, and Tangrowth can all learn sleep powder when they reach a certain level.
Wooper will evolve at Level 20.
You have to have it have high happiness. It doesn't evolve at a level.
LEVEL 25
Farfetch'd is a Pokemon that does not evolve.
22
you have to trade
Level 42
Level 21