I assume this is for USM. If so, Ludicolo and Megainium are outclassed by a lot of other Grass types. Also, you have less physical attackers than Special ones. Therefore, I recommend Tapu Bulu, Cradily, and Celebi as possible replacements. Moreover, if you use Cradily, you should change Ferro to a wall rather than a suicide lead. :P
Rotom-Mow needs Defog more than Hex or Leaf Storm because you don't have any ways of Hazard Removal or Prevention. :P