So... You want to learn how to play the tree? In this guide I will go into how to play the tree of doom as an an AP tank, or a pure tank. I am of no high elo by any means. I am just another player like all of you who gets by with normals and sometimes rank. At any rate I hope this guide will give you a better understanding, give you another route, because by no means should a build be set down by only one way. Versatility is always good, and Maokai is viable with a lot of builds. Personally when he came out I instabought him, but I never realized his true potential like many people until chu8. Although I didn't copy his build or anything, he inspired me to play Maokai again and actually try him out... I wasn't disappointed and I hope you guys won't be either. I just want to repay the community who taught me so much and allowed me to explore my own guides and builds. Cause to be honest, before I read guides here, I was terrible lol. This is my first guide for LoL ever. Anyways thanks!

Pros:
Extremely good at harassing.
VERY good at farming throughout the game.
Very strong pusher
Has huge base damage which help him a lot
His tanking ability is amazing
3 potential AOE skills
Amazing snare ability
Great iniator
He's a tree, need I say more?

Cons:
He's quite slow, since he's a tree.
Against smart players, harder to land saplings.
Early game, should play conservatively and not spam all his skills and go oom.

I get magic pen runes to help penetrate more damage, as Maokai has amazing base damage and you should abuse it as much as possible.
Armor seals are my personal favorite, I just find a tanky champ to be a good champ. Also because it's really cheap. If not, then feel free to get flat hp seals or whatever your little heart desires.
Glyphs, MR help a lot imo, although I run with flat MR simply cause I don't own a lot of rune pages and a lot of my other champs flat MR is better, however I think scaling magic resistance is much better. So get either.
Quintessences, let's be honest guys. Maokai is really slow. They sorta buffed his movement speed sure, but not enough. Therefore we take matters in our own hands and take ms speed quints. They're good with a lot of champs, you just can't go wrong with them. And if I don't have a solo lane to myself, I find myself roaming a lot and helping other lanes.

Typical 9/0/21 for caster. Why not defensive tree? Several reasons.
Frankly the 15% MR penetration is to good to pass up on as the game progresses, along with the cooldown. Again, you want to take advantage of Maokai's damage as much as possible, you wanna be a threat in teamfights, not just a walking tree in the middle of the fight who everyone ignores. You want to be noticeable!
21 in the Utility tree because I find it very useful. His teleport skill for obvious reasons, the exp up, Maokai wants to level up asap, and I'll explain why later. Greed because it may not be a lot of gold, but throughout the game its pays for several wards and its worth it in my book to save a few lives. His mana regeneration could use some love, so take 3 in that. And again, Maokai is very slow, so the 3 in MS is very important. Flash for obvious reasons. More cooldown, you want your skills up very fast, especially in teamfights.
The defense tree is good too, but I find that the other 2 trees are so much more useful and too good to pass upon. Although again this isn't a set guide, this is through much experimentation with Maokai and this is what I ended up doing. If you're all for the defense, go for it.

YES SPELLS
Teleport-Teleport is such an underrated spell. It can be used to save turrets, to backdoor, to push, to get to teamfights asap, so many uses. It's essential. And it helps a lot in solo lane to get back to the lane and not lose out on any exp or farm.
Flash-Flash is pretty much essential in games these days, flash to escape, flash to initiate blah blah. Well yes it's a brilliant tool to escape in the jungle, to flash in and steal baron all that nonsense. It's also good to flash in, and snare the unsuspecting victim. So many times, I've been able to catch that one last runner from escaping and ensuring the ace with a flash snare. It's good. Use it wisely.

Ghost is another viable choice, you're slow, you need to escape, pick ghost, although I prefer flash, it's a matter of preference. Pick what you're most comfortable with.
I sometimes go with Fortify since I like to fit in with the picture of pure tank. It really helps when the enemy team is pushing and nobody's there. It's a good summoner spell.

If you want to replace Teleport with ignite, although not recommended, you can. Since with ignite and your combo, you're almost guaranteed a kill.

Clairvoyance is okay, but only if there's no support on your team.

NO SPELLS.
Exhaust-You're no DPS, you have a slow, stop making things redundant.
Revive-Stop trolling you
Rally-BEASTIEST SUMMONER SPELL EVER... just leave it to the trolls.
Smite-Are you jungling? Cause I'm not.
Clarity-Next to useless late game, I don't find that I need it 90% of the time.
Heal-You're no soraka, stop trying to pose as one.
Cleanse-It's an okay spell... But with merc treads you shouldn't even need this.

You want to start out with the regrowth pendant and a hp pot for lane sustainability. Typically I like to take solo lane as Maokai, and anything that helps me stay in lane as long as possible is necessary. Usually I am able to stay in the lane until I get a philo stone and boots, a wards, some pots. If by some luck, the enemy laner overextends, you get a kill, or your jungler ganks and you get some extra gold, it'll be that much better for you. However it's not necessary. Having no kills is fine, just keep last hitting and win the lane, don't over extend and get ganked. After the philo and boots of speed, I like to rush catalyst cause again, you want to be able to stay in the lane as long as possible. This helps heal up your mana, and if you got ganked, then your hp too. Between your philo, your passive, and this, you're not going anywhere.
Rod of Ages, I used to think this item is ****. But it's simply a core item on Maokai, it helps him with everything. It makes him beefier, hit harder, and have a large reserve of mp to work with in teamfights, draining his ult allowing him to stay anywhere as long as you want.
You do not want any other gp5 item other than philo stone, it's unnecessary because Maokai is a hardcore farmer. You won't need them at all.
Wards save your life, get it all the time when your ward runs out. It's worth it for 75 gold every 3 minutes. And it won't take much of a chunk of your gold since you'll have a lot.
Merc treads if going tank, Sorceror boots if going ap off-tank. However if the other team has a lot of cc, then take the merc treads. I find myself needing it all the time so I suggest getting it.
From here it's always based upon the other team. If there are lots of ap casters getting fed or something, get some MR. Banshees veil and Force Of Nature are very good defensive items. Again if the AD carries are getting really fed, don't be afraid to get a thornmail or a frozen heart. Frozen heart would be the ideal item since it provides an attack speed debuff, gives you a CD reduction, and it's just an amazing item in general.
If they have a balanced team, I usually find myself getting aegies, banshees, and guardian angel. It just depends, decide for yourself what to get.
If going AP tank, then after ROA, I usually find myself with a lot of gold and am able to buy a Rabadons. Obviously it's not always the case so you can go with what you want. I find Rylais to be a bit redundant considering you have a snare and an AOE slow/small knockback. Just get what you always get for tanky ap champs lol. But even when building AP, it's good too have some defensive item too, since you'll be in the middle of the fight with your snare bringing you in, and your ultimate too. If built right, Maokai almost NEVER dies.
As always, keep getting wards for key locations if your team is stupid and never wards, and oracles/elixirs when your build is done. Cause when I Maokai, I usually have 200+ CS mid-late game depending if I get a solo lane, and sometimes more. And if you're a beast tree, you'll be getting a lot of kills/assists, not intentional kills of course but you have such high base damages, it's kinda hard not to kill. Anyways all that gold has to go somewhere, put it somewhere useful.

Maokai is simply amazing. His farming potential is so good. You'll want to grab saplings first level for some harass.
Here's something I usually do if we have no jungler and so I'm in a duo lane. I usually just Sapling the spot where golems spawn and kill them first. Note that only 3 are able to stay before the saplings just explode from being having too much swag. So I time the saplings so all 3 are there and it explodes on the golems. Then I'm able to throw another and kill the golems quite easily with the help of my other laner. This gives us both around enough exp to be at half way through lvl 1, giving us a huge advantage in the lane and being able to level faster then the others. I usually tank the golems and b then come back. So my laner friend is usually able to get to lvl 2 when I get back whereas the others are still lvl 1, and I'm still at decent exp.
Anyways, you want to get all 3 skills by lvl 3 to be able to unleash your deadly combo. Anyone hit by your full combo as E>W>Q will not go away without crying, unless they're some kind of juggernaut, in which case you should have lost the game already. You want to max Saplings as soon as possible. At lvl 3 saplings, you are able to throw it at the caster minions in the back and Q them to be able to completely annihilate them. This helps you farm so much. And by lvl 4 saplings, you are able to completely destroy the caster minions with 1 sapling, enabling you to quickly gain a lot of gold and dominance, at the same time pushing the lane. Do you care if the minions are at the tower now? Heck no you're not cause you have a ward alerting you to possible ganks coming in and your saplings have such huge range you're able to farm from safe distance. If the enemy laner is stupid and thinks he can hid behind minions to avoid saplings. Throw one at him and teach him a lesson, while gaining a lot of gold in the process.

E is maxed second for the snare duration. Q last since it's still good, but not as important as the other skills. NOTE not to Q immediately after snaring. It'll knock them out of the snare prematurely and you just let them escape like a lost noob. No you want to keep AA'ing them and then when they run you Q them and bam they're slowed. Run from the tree monster? I think not.
Maokai's ult has a really low cd. It is extremely underrated for what it can do. People usually commit into a teamfight against me and I just pop up ult and snare them in there, letting them attack me some more, and explode. The tank just got his kill BOI. The 20% damage reduction is extremely useful. It makes your team all that much tankier, although I don't know why they would be getting hit since you're gonna be up in the enemy teams face and snaring them and Q'ing them. They'll be running from you cause you're so beast. No, really.

You'll want to farm as much as possible, and get all your items cause when you get in a teamfight, they're all gonna die unless your team are complete morons in which case, just carry harder. You will dominate in team fights. Don't be afraid to lay down an ult cause you think a team fight is about to explode, your ult has an extremely cooldown.
Harass as much as possible, and when low enough, unleash the deadly combo for the kill. Normally with all tanks, you'll want to leave the kills to your carries. But when your carries are so bad, don't let them escape, don't be afraid to kill. Don't be stupid and initiate into a completely hopeless fight, be a leader, be a smart leader, lead your team to victory, not a complete ace for the other team. You'll know if you can take them or not. You're a tree for goodness sakes. In most cases, you are the initiator. You can decide whether you can win the game or not.
Don't be afraid to tank turret hits for your team, you're the tank. Always save the carry. You'll probably end up surviving anyways unless the other team has a huge amount of cc. If your ashe is running away with low hp and getting chased, snare that stupid noob trying to kill your carry and take the killing blow. It's a lot worse for your ashe to die then you, sorry to say. Unless again, your team are complete morons.
Ward dragon, baron, buffs frequently, map control leads to success.

Throw them saplings and win the game. kthxbai. Hope you learned something.