I didn't even have to do anything! With a levelled-up Shards, a maxed Stoneshield, Block and Stone Vines on auto-use, etc., I can just stand still and watch everybody around me die. It's slightly boring but cool as hell.
(Also, if you're putting Stone Vines on autouse, and you have the addon that automatically uses infusions/runes/talents to regen resources, make sure that you have the autouse only trigger when enemies are in view! Otherwise, you'll get caught in an endless cycle of vengeance and death with no defendents. Err, an endless cycle of "SV on, SV off, Meditate on, Meditate off, SV on...")