>>16567644HP grass 2HKOs Rotom-W, does more to Vaporeon/Politoed, and does the same amount to Azumarill, Keldeo, Starmie, and Gastrodon. The only viable water type Grass Knot does more to is Jellicent, and it's not that common.
HP Grass can be good depending on what team Greninja is on. It happens to be on one that doesn't like water types.
