So I check and see this is the 3rd top rated guide for the tree on the site! Thanks everyone for your comments and ratings. :D

New patch v1.0.0.112: Morello's Tome now gives 20% CDR. This is a nice buff for the build.

New patch v1.0.0.113:

Maokai

* Arcane Smash damage increased to 70/115/160/205/250 from 50/95/140/185/230
* Twisted Advance damage increased to 80/115/150/185/220 from 80/110/140/170/200
* Sapling Toss lifetime increased to 35 from 25 seconds.
* Vengeful Maelstrom
o Casting delay reduced by 50%
o Initial mana cost changed to a static 75 from 75/125/175
o Continual mana cost changed to a static 30 from 30/35/40 per second

Wow, what can I say, this is a big buff for Maokai, especially Arcane Smash. It might be worth putting in more points in Arcane Smash compared to Twisted Advance in early game now.

This is a build for Maokai. As a tank he is below average, but he makes up for this with his epic long range harrass abilities and the teleport on his Twisted Advance. This build is for when your team already has a tank and is a harrassment/pusher/support build. It will leave you with a good amount of AP, mana regen and cooldown reduction early game, as well as some needed HP, armor and magic resistance so you survive teamfights late game.

This build works great on a solo lane. Just harrass with Sapling Toss, root them if they try to damage the tower, and root into quick sapling into Arcane Smash if they get on low HP. It will finish them nicely. This build is also fine for dual lane however.

This build is NOT good if you are the only tank on the team. Check out the "Iced your Killing Tree" build for a more tanky build that still has some AP.

Haters gonna hate, but I do not think tank Maokai is the best way to build him. He has such great range on his abilities, that he does not need that much early game survivability.

If you are still in disbelief, then here is an example of when I got the full build:

The twisting magical energies unleashed by mages during the Rune Wars caused an incredible amount of devastation to the natural world. The League was established to control the use of this magic by confining it to the Fields of Justice. By limiting its use to there, they thought that they could prevent it from doing further harm to the environment. It seemed that they were successful until Maokai came into being. During a League match on The Twisted Treeline, Maokai, an ancient oak that stood above the upper jungle, spontaneously roared to life. Ripped from the natural balance by arcane forces, his sentience was forged in chaos. Before the Adjudicators of the League could step in and suppress him, he slew all six champions participating in the match. The scholars of the Arcanum Majoris took a keen interest in him, as they were eager to discover the secrets of his animation.

Maokai was furious, however. He abhorred the existence was that thrust upon him; he felt it was a corruption of nature. He learned to communicate with people in hopes of finding a way to be returned to his former, true state. Seizing the opportunity, the League offered a trade. They would research a way to revert him so long as he agreed to fight in the League of Legends. Maokai was indifferent to verdicts rendered by the League, but he was eager to punish summoners for their wanton use of magic. He agreed to the terms under one condition: once they learned how to turn him back, they would never animate another tree again. He wears a lantern on the Fields of Justice to set him apart from the other trees, and as a warning to the animals that would do him harm.

I will use this power until I am free of it.
- Maokai

Pros

-Great range on abilities.
-Saplings are cute AND deadly.
-Great for punishing pesky mages, or just rooting tryndamere to the spot and watching your team unload on him.

Cons

-Easy to get mana starved (this build compensates for this).
-Not the tankiest of tanks (especially with this build).
-Initiate, but no flee.
-Lumberjack Sion can chop you down.

Greater Quintessence of Health for survivability. Mana regen and CD reduction are important in the build = MOAR sapling tosses. Finally Greater Mark of Magic Penetration are very useful, especially if you dont buy sorceror's shoes.

Utility is hands down the best mastery tree for me, and especially for Maokai as it provides great cooldown reduction, max mana increase and mana regen.

Next comes 9 points in offence for the 15% extra magpen and again CD reduction.

I actually run 9/0/21 for most of my champions, the cooldown reduction is just too good to pass up.

This build is focussed around Sapling Toss and how amazing and fun it is to use, so we buy a first. You may also want a if you are scared of early game harrass. As for the boots, is definitely optional, you may want to get sorceror's shoes or ionian boots or depending on their team. If you are playing solo queue I recommend , as it means you can outrun most champs to get that all important Twisted Advance off. The rest of the items are pretty self explanatory, abyssal sceptre gives you some nice extra mapgen when you twisted advance onto someone. The last item doesn't have to be Zhonya's Hourglass, you may want Rabadon's Deathcap instead, or even Guardian Angel, depends on their team.

Sapling toooooss! Then Twisted Advance. Since the new patch, the damage on Arcane Smash is much higher, so I recommend putting more points into it early and not neglecting it entirely.

Ghost and Teleport allow you to get around to where you are needed quickly, which helps your role as support. It is easy to tele in and twisted advance at a crucial moment, or just to help you get back to lane faster if you are on a solo lane. Remember, keep those turrets up, they are worth 750 gold to the enemy team for each that is destroyed. :)

What makes Maokai special for me is the epic long range on sapling toss and twisted advance. It is sometimes possible to twisted advance onto someone on a tower from inside the jungle. Also sapling toss has such ridiculous range that you can easily bomb people who towerhug. You will find this has the effect of helping greatly when your team is pushing, by preventing the enemy squishy champs from clustering around the tower.

Warning: saplings are stupid and just chase the nearest thing they land next to, so it takes practice to land them so that they hit enemy champs. Faster enemy champs can also outrun them.

Protip: If an enemy is hanging around the tower on low HP, dont hesitate to dive them to get the kill. You have a decent burst with E->W->Q and they will not expect it coming from a support. :P Mid game you can probably take at least 4-5 tower hits even without armor.

Maokai's ulti... is a bit underwhelming. You can use it to finish someone who is fleeing on low HP, because of the range. If you are lucky enough for a big teamfight to start near you then definitely throw it down, but keep an eye on your mana because it burns it up fast! The good thing about it is that you can still root and toss saplings while it is active. The bad thing is that if you are not careful you will waste all your mana and only do little damage with it. It is definitely useful, not not gamechanging like Nunu & Willump's ulti, Fiddlesticks's ulti, Katarina's ulti, Amumu's ulti, Galio's ulti, Gangplank's ulti....

In my opinion Riot should make it slow the same as Anivia's ulti does, but hey they probably know better than me.

Edit: That's more like it. In the new patch they reduced the casting delay and the mana cost, so it is now a lot more effective and doesn't burn away all your mana.

Farming is essential for every champion. The thing that separates the good from the best is the ability to last hit and farm the jungle effectively. Luckily for you, Maokai is a great farmer when he has enough AP and Mana regen.

Wraiths, then wolves, then golems are the easiest to farm in that order, but they will all die pretty fast. If you toss your sapling right, you can take out some or all the wraiths without having to go near them. Profit!

I also recommend getting blue buff, if no-one else on your team needs it more. You can bring down ancient golem faster than most mages because of your surprisingly high AD. Actually just spam all your abilities on it (including twisted advance) and it will die fast, then you have the sweet mana regen and cooldown reduction of blue buff and can skill spam like there's no tomorrow.

Try to encourage your team to get dragon, you can help but definitely not solo it. When it comes to laning, it is tempting to try and last hit with Q, but don't waste your mana. Sapling toss is where it's at. Sapling toss, like Teemo's mushrooms, is good for farming waves of minions as well. Don't waste it on farming early game though, save it for late game when you have the mana regen and CD reduction to spam your skills more.

In my example game I have 244 minion kills and 43 neutral monster kills, and it wasn't a very long game (or I would have more kills). Farm like this and you will get a massive gold advantage, making the game easy.

All in all, although Maokai is a bit expensive at 6300 IP, he is a really good and fun champion to play with some unique skills that mark him out. For me although his abilities do not scale incredibly highly with AP, AP hybrid Maokai is still a world ahead of pure tank Maokai. If you do not believe me then please try it yourself, don't just downvote without trying the build.

Thanks for reading the guide and gl hf punishing those pesky mages (and everyone else).