[TigerBlood]

They are mindless, poison immune, sacks of hit points.

They work best when buffed. Nature provides a lot of usful buffs for them, like regeneration, though other paths can make them fairly effective in numbers.

With 45 hp,they are decent blocking units. They will probably be attacked in preference to your jaguars. If you script a force, you can easily force melee or archers to target the vine ogres in preference to other normal units, allowing your jaguars to flank or surround an enemy squad when they hit the wall of vine ogres. This kind of basic tactic works best when the VO are heavily buffed.

Like undead units, they can also be used to compliment poison using units at no risk of banishment. Such as creatures with a poison cloud (eg. Monster Toad), or creatures that have a poisonous ranged/area attacks (Amphiptere, Bog Beasts, Breath of the Dragon, Snake Bladder Stick).

Their use does depend on what else you have available though.