Disclaimer: do not use this guide if you have never played Heimer before

Give this guide a chance, I have been playing Heimer ever since I started playing this game. I know a lot about the champ and how he currently plays. Give it a try before you completely dismiss it. And if you try it and do not like it please explain specifically what problems you had. Also keep in mind that this is not for competitive play. All in all it's just fun as hell to play once in a while.

Here is a video of someone who clears the jungle as Heimer. Play Video
I am not the best at this game, but I can do alright, as seen in this stretch of win streaks using this build:

Pros:
Self leashing turrets
fast jungle clear time
Can gank immediately after getting red buff
Passive healing gives him sustain in jungle
Does not over push your lane
Does not get ganked in middle
Does not just get rolled over at top
Does not steal your CS
Has zone control with turrets/slow
Has blind/stun
long range missiles
Good bait for greedy champs
decent dps

Cons:
There are stronger jungler choices
Heimer always needs blue buff
His CH-1 Concussion Grenades are hard to land
He's squishy
His damage output is limited
Relies heavily on a successful first gank in mid
Relies heavily on competent teammates
He's slow

I have tried 9/0/21, but the utility tree is just so underwhelming. However, if you have never tried heimer before I strongly reccomend this guide..

By going 21/0/9 you beef up your stats with only really losing the 6% CDR, which does actually hurt a bit. More Damage will hopefully make you a more viable ganker. Unfortunately if you want the 10% Magic penetration in Offense you cant get Summoner's Resolve for the bonus 10gp per use. However, I figure the extra Magic penetration is worth the loss in gold.

I have not tried putting more points into Swiftness , because I always need more mana, but its a possibility that could be explored.

Standard, good early damage. Though once I learned that Rabadon's Deathcap also took into account ap from runes I must admit I was tempted to switch these into ap runes. But I don't know if the sacrifice to early damage is worth the nominal gain from Deathcap.


Heimer is pretty mana hungry, these help a little. Hopefully you will always have the blue buff to help you out though.


You want as much CDR as possible on Heimer. These help you lay down your turrets more often and spam your abilities.


A must have item, the only way a heimer is going to be able to "gank" at all is if he has as much movement speed as possible. Not to mention it allows you to kite around your turrets and tower longer.

Since we want to gank immediately after red, this seems like the best set up.


On your first trip back buy Sorcerer's Shoes and start building Rabadon's Deathcap. This will give you good movement speed and quite a bit of damage. Rushing Rabadon's Deathcap will make it so you are dealing out hefty amounts of damage as soon as possible.


Standard if they have lots of CC and are worried about it.


Once your deathcap is done, the next item depends on how you are doing and what you are worried about facing. If you need Magic resist, buy a Negatron Cloak, if you need more armor, buy a Chain Vest. However, if you are doing well save up to buy Needlessly Large Rod and build it into Zhonya's Hourglass. The active on zhonya's will make it much harder for the other team to focus you.


Rylai's is a good buy next, giving you health AP and a slow to help in team fights. (Note that the slow only procs on his CH-1 Concussion Grenades and Hextech Micro-Rockets, but his Hextech Micro-Rockets give the full 35% slow.) This item can be swapped for Rod of Ages as suggested by Roronoa EvrIs.


Build Abyssal Mask if you want some more MR and want to deal a little more damage.


If you notice your opponents getting wise and building MR this is always a good choice.


Both could be good late game, Will of the Ancients would go well with your Abyssal Mask during team fights, plus giving your team sustain never hurts. Rod of Ages will make you tankier and will be a more forgiving item if you happen to get caught in the middle of a team fight and Zhonya's Hourglass is on cooldown. Rod of Ages can be bought before Rylai's Crystal Scepter. They basically do the same thing, but ROA gets better the longer you have it, and the slow from Rylai's Crystal Scepter, although great to have, is not always necessary, it is up to preference.


I do not have these in my build, because ideally you will always have blue which takes the place of these items.

A point into turrets to leash, then into CH-1 Concussion Grenades to stun and blind Creeps. Next get Hextech Micro-Rockets for added burst damage. get to lvl 3 Turrets and then max Hextech Micro-Rockets. Next finish off Turrets and lastly CH-1 Concussion Grenades, putting a point in your ult whenever possible.

Maxing Hextech Micro-Rockets will give you a lot of poke and can give you kills that you otherwise would not have gotten if you went turrets first. CH-1 Concussion Grenades function as an important source of burst damage/blind/stun. The more points into it you put the longer the blind is, but the stun stays the same.

The key to any good heimer is being able to predict the movements of your opponent and landing your CH-1 Concussion Grenade more often than not. Remember to use this skill when people are meleeing you or chasing you. Another key time to use this spell is when your opponents are all clustered up in a group fight. Being able to blind 2 or 3 of them and possibly stunning one can turn the fight to your teams favor.

When using his Hextech Micro-Rockets always keep in mind which targets are the closest to you and once the minions between you and your opponent become 2 or less you are free to poke them with your Hextech Micro-Rockets.

I love ghost, I think that this is a must have on a jungle heimer. It is a great escape tool or ganking tool and has a lower cooldown than flash. Furthermore you can use ghost to kite around your H-28G Evolution Turrets a function that I don't think everyone realizes.



Must have if you want to survive the jungle.


Of course summoner spells are mostly up to preference, here are some others that are pretty good. Exhaust could replace ghost and may be the better pick, as it also weakens your opponent's attacks and defenses while making it harder for them to escape your turrets.

With both buffs you ghost in to where your opponent will try to retreat to. Place a H-28G Evolution Turret there so if they take that path they will take turret aggro. Or if they are fleeing try to predict their path to land your stun. place turrets between where they need to go and themselves. Use UPGRADE!!! on the H-28G Evolution Turret and use your Hextech Micro-Rockets. If this does not put them in a position where you can auto attack them to death or rocket them into death, then you probably shouldn't have ganked them. :p

Interestingly if you fail to gank, and start taking damage, you can now use yourself as bait, to get them to over extend. Hopefully either you or your teammate can then punish them for trying to pick on the squishy jungler.

Wow! Thanks for all of the feedback! I thought that this build would just be neglected, but keep the feedback coming.


Response:
I like mental force better than Butcher because the turrets get a benefit from Mental Force, and they are the ones that do most of the damage. I also choose Havoc because it increases all damage not just damage done to minions. That being said, you could easily tweak it to your personal preference like you said.



Response:
All valid points, I try to mitigate heimer's speed with speed quints and getting boots early. And if you cannot reliably hit the person with your stun or blind, then you are going to have a really tough time with the gank. Ghost goes a long way to helping you catch up to your target and placing turrets down so that your opponent has to retreat in a different direction, hopefully in a way that allows your allies to punish them.



Response:
I found that IF the first gank in mid goes in my favor, I am able to get enough items to gank successfully for the rest of the laning phase. But you are right that if the ganks aren't in your favor it becomes very tough to buy the right equipment at the right time in the game.

2/23/12- Guide updated for Jungledinger
6/10/12- Discussion