>>52953494>>52953452Where the fuck did you two learn to play pokemon? Mono grass has more weaknesses than grass/poison. Adding the poison type means you are no longer weak to poison or bug and you resist fairy, but ground is neutral and you are weak to psychic.
The only difference in their offensive coverage is Vileplume gets STAB on Sludge Bomb, they both get Sludge Bomb, Giga Drain, Moon Blast and Hidden Power and Nature Power in older gens.
