I've been running some mono teams through SS recently. My grass team consisted of: victreebell, sunflora , tangrowth, meganium, bellossom , and sudowoodo (cheating I know but it fit in at the time).
Honestly from all the grass types in the game, bellossom is the beastliest.
Huge sleeper.
Sunflora is good too if you want to stall with ingrain /leach seed.