One of the few crowd control spells not subject to creature type restrictions (humanoid, beast, demon, etc.). It is, however, unreliable. Any creature that is immune to nature spells, as is common among elementals, is immune to Entangling Roots.
Patch 4.0.6 (8-Feb-2011): Entangling Roots now has a PvP duration of 8 seconds.
Patch 3.0.8 (2009-01-20): When determining if a new Entangling Roots should overwrite an old one, and will now calculate the correct damage modifiers for the creature type of the target.
/Patch 3.0.2 (14-Oct-2008): Entangling roots is now usable indoors.
Patch 2.3.0 (13-Nov-2007): It is no longer possible for multiple Druids to have Entangling Roots on the same target. In addition, it will now always be removed correctly if multiple Druids overwrite each other’s Entangling Roots.; This ability will no longer be overwritten when the new Entangling Roots would do less damage.
/Patch 2.0.1 (05-Dec-2006): All crowd control effects have a chance each second to break earlier, and their duration is capped at 12 seconds in PvP. The chance increases with resistances and the level difference between the target and the caster.
Patch 1.7.0 (13-Sep-2005): Entangling Roots now shares the same duration in pvp as other long-duration forms of crowd control (ie: polymorph, fear, sap).
Patch 1.4.0 (2005-05-05): Now subject to diminishing returns in PvP. This is considered an immobilizing effect.
Patch 1.2.0 (18-Dec-2004): Entangling Roots: Rank 4 moved to level 38.