Exeggutor

Chlorophyll
Speed doubles in sun.
Type Tier
Grass / Psychic BL
Statistics
Min- Min Max Max+
HP
95
- 331 394 -
Atk
95
203 226 289 317
Def
85
185 206 269 295
SpA
125
257 286 349 383
SpD
65
149 166 229 251
Spe
55
131 146 209 229
Name Item Nature

Chlorophyll

Leftovers / Lum Berry / Heat Rock Modest
Moveset EVs
~ Sunny Day
~ Sleep Powder
~ SolarBeam / Grass Knot
~ Explosion
4 HP / 252 SpA / 252 Spe

Of all the Chlorophyll Pokémon, Exeggutor has the highest Special Attack. Use Sunny Day to double your Speed and turn SolarBeam into a one-turn 120 base power attack, put something to sleep, fire SolarBeams until you're tired and go out with a bang. Grass Knot doesn't have 120 power against everything, but does strike most Pokémon SolarBeam is intended for at high enough power, and doesn't make Exeggutor instantly lose against a Tyranitar or Abomasnow switch-in. Blissey isn't going to wall this all the time: she can be put to sleep all the time and forced to go away with Natural Cure, or be blown up on to clear the path for another special attacker. If you can obtain an Exeggutor with a good Hidden Power Ice or Fire you should consider using it. It helps against other Grassers—the former beats down Salamence in one hit while the latter is more powerful in the sun and hits Steels not named Heatran (and perhaps Empoleon) hard.

Lum Berry is optional because it's really hard to sweep if your Speed is cut down by paralysis or you lose health every turn due to poison or burn. Heat Rock makes the sun last longer, which can be good for both Exeggutor and his teammates if you tune them to it. Fire-types and Metagross are good examples.

Name Item Nature

Tank

Leftovers Relaxed / Bold
Moveset EVs
~ Sleep Powder
~ Explosion / Wish
~ Leech Seed
~ Grass Knot
252 HP / 80 Atk / 176 Def

Exeggutor's HP and Defense are in fact pretty good and he resists Earthquake, so this set takes advantage of all that. Grass Knot is a solid STAB attack that hits at a high power on nearly everything Exeggutor would use it for. The problem is the pretty abysmal Special Defense and the huge amount of weaknesses Grass and Psychic bring together. Mr. Coconut is weak to Pursuit, and nearly every threatening physical attacker carries a super effective move on him. Salamence can use Fire attacks, Rhyperior has Megahorn, Tyranitar has Crunch, you get the idea. You still get to put one Pokémon to sleep and Explode on another though. Wish is an alternative to keep Exeggutor around longer and offer team support.

Name Item Nature

Choice Specs

Choice Specs Modest
Moveset EVs
~ Leaf Storm
~ Psychic
~ Hidden Power Fire / Sludge Bomb
~ Explosion / Grass Knot / Energy Ball
252 HP / 252 SpA / 4 Spe

Exeggutor is hard to switch in properly, but 125 Special Attack with Choice Specs will be inflicting pain. Leaf Storm does major damage, Psychic is for secondary STAB and your third move is mostly to cover things that resist Leaf Storm. All three take care of most enemy Grassers. The Chlorophyll set description tells you what they cover. Sludge Bomb is more accessible for in-game battlers, though Hidden Power is preferable. Explosion in the last slot can be used to take out the opponent's special sponge, or you can use another Grass move without the Special Attack drop Leaf Storm has.

Name Item Nature

Uber Exeggutor

Leftovers Modest
Moveset EVs
~ Grass Knot
~ Hidden Power Ice
~ Sleep Powder
~ Explosion
4 HP / 252 SpA / 252 Spe

Exeggutor's use in Ubers is to abuse the sun Groudon brings. Grass Knot OHKOs enemy Groudon, Sleep Powder and Explosion are the usual "we must kill SOMETHING with this thing, right?" options and Hidden Power Ice is for that Rayquaza whose threat level has been raised in Diamond/Pearl. You won't do much to other Psychics, especially not the Lati twins, unless you want to use Thief Exeggutor of course, which is not a bad idea. Stun Spore can cripple things as well.

Other Options

Wood Hammer hurts with STAB and immense base power, but the recoil might turn you off. Seed Bomb is a less powerful substitute, but has no side effects. Thief is a good option on any set but especially the uber set. Thief steals an item which can be quite a nerf for your opponent. If you get Leftovers, they lose their recovery and will be worn down. If you grab a Choice Band, your Explosion is now boosted. If you got Choice Specs, fire away with your main STAB. Stealing a Soul Dew basically means Exeggutor's job is done, as he's removed the Lati auto-Calm Mind all by himself. Stun Spore is good to catch fast Dragons in any metagame off guard, and of course Weavile and other sweepers. Trick Room is pretty good on Exeggutor as he's slow enough to go first most of the time and durable enough to set it up, Protect helps you scout the opponent.

You may have note a saddening lack of Psychic in Exeggutor's movesets, which was very prominent in the other generations. The reason for this is that Dark-types got a lot better in Diamond/Pearl, and that Psychic is not effective at all in the Uber metagame. It helps to hurt Heracross on the switch, obviously, so consider it an option.

EVs

If you plan on using Chlorophyll, max out Speed. When using Exeggutor as a defensive Pokémon he should have max HP. A lot of whichever attacking stat you're using is good. When Explosion is your only physical attack, you can pump EVs to about 245 to kill Blissey with it, but that requires quite a lot of EVs and a nature that either hurts your Speed or your durability.

Opinion

Exeggutor has the horrible tendency to take a hit every time a new generation comes out. He was basically an obligatory Pokémon in the RBY generation when he had astonishing Special, but nowadays Exeggutor has so many issues even 20 Mr. Mimes can't count them on all their hands. Celebi outclasses him as a defensive Grass/Psychic, his Special Defense prevents him from tanking really well on the special side while a weakness to Pursuit, Ice, Fire and Bug does him over on the physical side. He is slow as dirt as well.

There's also some positivity under the sun, of course. Exeggutor's movepool didn't grow much since the last era, but he can still Explode on Special sponges, use Sleep Powder and Stun Spore, and knock off quite a lot of points with his 125 Special Attack.

Counters

Every time you switch in a counter, you risk that Exeggutor puts it to sleep, paralyzes it or suicides. Just so you don't think you're completely safe.

Either Salamence or a Steel like Skarmory, Forretress or Scizor, will always wall Exeggutor, because he can only use one Hidden Power and it won't get rid of both groups. Exeggutor is weak to Pursuit, so he can be assassinated by Weavile, Houndoom and Tyranitar. Any Fire-type can fry him more quickly than the French can say "qu'est-ce que c'est?", Heatran and aforementioned Houndoom in particular as they aren't crippled by Psychic. Most Ghosts can land some super effective STAB on him as well, but Gengar obviously should be wary of STAB Psychic. Celebi forces him to blow up or choke, unless you've got Hidden Power Fire boosted by Sunny Day. Poison-types in general take Exeggutor on if he's not carrying Psychic as his STAB move: Crobat and Weezing are some more common ones. Abomasnow can change the weather and cripple Exeggutor's sweeping potential.

You don't want Exeggutor to be statused, especially not when you're trying to use Chlorophyll.