The quote from the area types was meant to say that it targets specific things in the area, not the entire area.
The spell descriptions entry specifies the difference between a regular burst/spread (fireball) and specific target-bursts (entangle). It's kind of like the difference between a regular high-explosive warhead and an MIRV. One hits everything in the area; the other is limited to specific targets in the radius, but it affects only those.
Entangle's area entry says "plants in the area." It specifically targets the plants, but neither the creatures nor the area. It's kind of strange to rule that a level 1 spell can make a potted cactus on a shelf entangle someone eighty feet away hiding behind a pillar (the spell is a spread, after all, not a burst) with no save, attack roll or grapple check, as long as he's in the area--let alone everyone in the area regardless of cover. Furthermore, the default shape for bursts and spreads is a sphere, so does that mean if I had a single dandelion growing on a rock, I could turn it into an entangling 40-foot diameter sphere of briars that can snag flying creatures?
And I thought Black tentacles was annoying.
I don't think a level 1 spell should be able to do this. (The sunflower tentacles starting from 1:05)