Poor Zarude. At the beginning of the generation it would have been the premier physical Grass type with a nice Speed stat and impressive ATK stat alongside above average bulk. However, with Rillaboom getting Grassy Glide and Grassy Surge in addition to having access to Knock Off, Zarude has been outclassed by the other ape in the jungle. Grass-Dark is also a rather unfortunate type combination, tied for providing the most weaknesses in the game.
Welcome to the Jungle
Zarude
Ability: Leaf Guard
Item: Life Orb
-Power Whip
-Rock Slide
-Stomping Tantrum
-Taunt/Jungle Healing/Crunch/Protect
Nature: Jolly (+SPE, -SATK)
EVs: 4 HP/252 ATK/252 SPE
Knock Off aside, Zarude has a surprisingly good movepool for a Grass type, having Ground and Rock coverage moves in addition to Fighting and its STABs. Rock Slide and Stomping Tantrum are especially good in doubles, considering the spread capabilities and flinch chance of Rock Slide combined with Stomping Tantrum having plenty of chances to get a boost thanks to how common Protect is. Power Whip is the requisite STAB and hits Water types (always good) and Ground types who would otherwise weather Zarude's coverage moves. Final move is up to preference. Taunt is great in doubles for Blocking Protect + the various other setup moves flying around. Jungle Healing has a unique niche, allowing Zarude to function as a Cleric, voiding Sleep, Burn and Paralysis while providing some healing on top of it. Crunch is a good alternative STAB if Zarude's support capabilities are not needed and Protect is always good in doubles.
Other Options
Assurance -doubles to base 120 power before STAB if your opponent takes damage before Zarude strikes. However, Zarude is already on the fast side and unless you are using a spread move, double targeting an opponent just leaves you open to being nulled completely by Protect which makes the move unreliable.