It seems that almost all of my druid grove attempts fail because the boss keeps teleporting behind a barbing bramble. Occasionally I'll be able to get at him with a WEYTWUT combo or break through the walls, but this costs a fair chunk of mana just to get back to the fight and doesn't prevent him from just teleporting back later (this is what happened to me in my most recent run; I used WEYTWUT to extract him, then used WEYTWUT on another monster to extract myself, then hit him and he teleports right back into the same little alcove). It's bad enough when I have to mana burn myself to run after him in some situations, but the brambles are game-enders. Often times this only happens after the map gets absolutely littered with plants in longer attrition battles, but occasionally it will happen early. A few attempts back I got trapped on my third hit, as he teleported away from a dead-end corridoor and left a bramble to trap me.
The berserker gets the job done quickly enough, and high-damage classes in general can take him down before he puts down enough plants. However, a more attrition-minded class (such as a bloodmage) needs to wear him down and this really causes the map to get littered with plants. At a certain point, the boss gets jammed behind brambles and I cannot touch him. In many cases, I'm on course to coast to victory if I don't take too many additional mana burns. Losing this way isn't fun or challenging, this is just plain frustrating.