>>13854513It might lose Leftovers, but it's got Leech Seed, Ingrain, Toxic and Curse. It can stall the enemy to death while racking up its (already improved) physical Defence without being Roared out, and that's nothing to sneeze at.
Or, you could trade a move for Synthesis, and heal large amounts of HP at any given time.
If you absolutely HAVE to use a directly-damaging attack, you can always use Knock Off for an anti-Mega strategy, and remove Mega Stones (or other held items, if Megas can't lose their item) from the enemy.
Thick Fat is a damn good move, especially for a Grass-type that specialises in stalling.