Blackened Treant  

Many spoilers talk about this being a timed spawn. Not so. It's spawned by the questing druid when the druid gets close to the lakeshore in the south-east corner of Kithicor Forest. So set up your raid in south-east corner of the zone while the druid waits at Commonlands zone, then when ready let the druid run near the lake and pop the treant. It is not aggressive until engaged. Note, the druid has to gain aggro or the final mob (Blackened Dryad) will not spawn, so one good idea is to let the druid pull the freshly popped Blackened Treant to the raid. This will of course put the questing druid on rampage, so be ready with a few heals. Done solo with 85 druid and tank merc.

Ok we just raided this thing and needed to do it for another Druids 1.5. since there is no info on it I thought I would share that after first raid <which took about 30mins to complete> I sat and waited for respawn and only had to wait 30 mins for a new Blackened Treant to spawn on my head.

So respawn timer on this guy is right at an hour unlike most of the Druid Epic 1.5 battles.