I am 20% sure that it grotle should evolve 23 episodes after EP603
ash's grotle will evolve in the battle againts Cynthia and the elite four
Not yet
Yes, Buizel will evolve into Floatzel, Chimchar will evolve into monferno, Staravia will evolve into starviraptor, and grotle will evolve into tortera.
Ash's Grotle evolved into Torterra in the episode that's titled "The Fleeing Tower of Sunyshore."
It evolves in the battle against Cynthia.
Possibly, but I don't think so. Most of Ash's Pokemon choose not to evolve, besides Grotle had trouble with dodging when he just evolved, and he'll have even more trouble with dodging if he does evolve into Torterra.
Ash's Grotle evolved in the episode "Aiding The Enemy!". It evolved during a battle with a trainer's Honchrow.
Ash's Grotle evolved into Torterra in "The Fleeing Tower of Sunyshore!", episode 166 of the Diamond and Pearl series and episode 632 overall.
Ash's Grotle evolved into a Torterra in The Fleeing Tower of Sunyshore
Yes, Ash does allow his Turtwig to evolve into Grotle in "Pokémon DP (Diamond and Pearl) Battle Dimension." Ash's Turtwig will evolve into Grotle in the episode that is titled "Aiding The Enemy" whic is episode number 1,148 and according to the Japanese airings it is episode number 100.
Grotle grotle
It has.