The Entangling Roots passive skills Imbued Sap, Spriggans of the Grove and Wardens of Farwood no longer apply a damage increase or cast speed increase to the Spriggan minion.
I’ve tried self-cast Entangling Roots, Werebear Roar-triggered Entangling Roots, dismissing the Spriggan then relogging and summoning it again, removing a point in all the above mentioned passives as well as Grove Master (AoE increase) and Vale Assault (Spriggan projectile modifier). I’m keeping the Spriggan firmly inside of the area of effect of Entangling Roots.
This goes for Training dummy as well as in combat, so it should be relatively easy to test.