Procs off melee only, does not proc off spells or ranged attacks.
Entangling Roots can be resisted - so even when Nature's Grasp procs, it can fail to have an effect.
Tips and tactics[]
This spell is very useful against melee attackers in PvE or against Warriors and Rogues in PvP.
Activate this spell when running away. Often the attacker will be rooted and unable to follow.
This spell is also useful for gaining range against a Shaman to use [Innervate].
It is entirely impractical for raiding if the druid is not a tank, given that 1) the scariest mobs are immune, 2) the druid shouldn't aggro away from a tank, 3) the druid is not likely to survive a single hit from such a mob, and 4) a rooted mob will turn to attack other people in range, regardless of aggro, potentially killing others in addition to the casting druid.
Now a level 10 ability for Balance druids instead of a talent.
Can now be used and can proc indoors.
Patch 2.2.0 (2007-09-25): This ability can now trigger while the Druid is sitting.
Patch 2.1.0 (2007-05-22): This spell no longer costs any mana to cast.
Patch 1.9.0 (2006-01-03): This spell can now trigger from special melee attacks. It will no longer be possible to cast Entangling Roots at no mana cost immediately after Nature's Grasp procs.