The porcupine cacti and tumbling mound (both from Sandstorm) have abilities that might work for the "bite" attack:
Thorns (Ex): A porcupine cactus's thorns tear at any creature that touches it, dealing 1d4 points of piercing damage. Creatures that strike a porcupine cactus with natural attacks or unarmed strikes, or that try to grapple the cactus (presumably to pull it out of the ground), are subject to this damage, but creatures striking with melee weapons are not. A creature that is pushed into or falls onto a plant also takes damage from its thorns.
The tumbling mound's thorns are similar, except it also has a slam attack and improved grab. Since the archer bush is mobile, it could use its thorns offensively by charging into someone.