Also, What are the best Poke Balls to catch it with?

Umm i recommend saving your game once you find it and throw a few quick balls to begin with then some ultra balls and if you dont catch it after like fifty pokeballs then just close the game and youll start where you saved just repeat that process until you catch it.

3 (Extremely Low) so go for the Master Ball. As a grass type it is unaffected by Sleep Powder and Spore, and some of them pack healing moves too.

Oop, i guess i was lucky to catch it with like my 5th ultra ball then ;w;