Rift Quest:Knockoff  

When the Wardstone is activated you will see a broadcast message, "The Defiant have begun to collect Rift Bloom at the Auld Warden!". This is also the signal for all Guardian forces in the area to move to stop you. You receive a buff, Blessing of Battle, as well to help you survive this trial.

In out of the way places within the ancient tree you will find a Rift Bloom. Harvesting it gives you a 3 minute buff called Rift Rage. Get back to the wardstone before the energy fades to charge the wardstone. You must do this 8 times.

The only Rift Bloom we found was on a root off the lip of the platform and we fell trying to get back up. Because of the Rift Rage we survived the fall!

The Rift Bloom is found on the 'roots' extending from the tree at great heights. Look there, sometimes there is as many as 3 on a long root section. - Zanathos

There is a portal at the bottom of the tree that teleports you to the top of the tree if you have the rift rage buff on you. -Jonnnney

The Guardian version of this quest is Keep Away.