Step into each rainbow area on the floor to make the desiccated growth mobs visible so they can be slain. These will appear as a visage of growth until attacked, then respawn as desiccated detritus. Do this around the entire room.
This may be unnecessary in normal mode, but is important when you do Graceless mode as each named has stacks and you'll want to kill the corresponding mobs revealed when on the rainbow area in order to drop those stacks.
Spawns 2 types of leaf piles around the room at around 75% and 20%. Some of them are infested, and will spawn adds if cleared. He will call the number of piles he wants cleared; do not clear the infested ones.
If you hover your mouse over the pile it will be labeled as either "Infested Pile of Refuse" or "Pile of Refuse." Only click on the ones that identify as "Pile of Refuse" or you will get a swarm of adds. You must be close to the pile to read which is which.
Ganadan casts Leaf Sickles on player around 95%, 70%, 45%, and 10% and goes invisible. Step into rainbow to make Leaf Sickles curable and remove detriment to see mob again.
Around 60%, Ganadan casts Hunting Party and summons several adds.
One approach to solo'ing Ganadan is to go around the room methodically stepping into the rainbows and eliminating each and every Desicated-mob that you can find around the room, BEFORE you tackle Ganadan. They don't seem to respawn after you kill them, so if he has no mobs he can summon, then he's less challenging to take out.
Around 80%, Anirath stops attacking and summons a storm of detritus. You will get the message, "Clear (#) piles of refuse to break the storm, careful of those which are infected". Remove the requested number of non-infected refuse piles.
When you see the emote"Anirath Andirin attempts to forget the past! Interrupt him quickly!", if you do not interrupt him, he temporarily removes the two rainbow areas closest to him.
At 50%, he casts Hunting Party and summons several adds.
