The awaken spell can turn a tree into a plant creature, which “has characteristics as if it were an animated object, except that it gains the plant type and its Intelligence, Wisdom, and Charisma scores are each 3d6.” But as a 5th-level spell it doesn’t help you much more than animate plants does. The benefits of having those mental ability scores are pretty solid, so it is plausible for a lesser awaken spell to exist and produce less-intelligent plant creatures. However, none does.
Looking into the animate objects spell itself (which would be valid for plant-objects as much as it is for other objects, so could be an alternative approach), it is even less helpful (6th-level spell and creates Construct-type creatures instead of Plant-type creatures, even when targeting plant-objects), but we also see room for reasonable downgrades: it affects a lot of objects at once. But no animate object spell seems to exist.
Finally, I want to note a similar spell along these lines that does have a lesser variant: animate dead. The lesser animate dead spell produces a single undead minion of no more than twice your caster level in HD, and you cannot have more than four times your caster level in HD of undead minions at a time.
So then, how about a bit of homebrew? I am considered pretty good at it, and this is pretty straight-forward, I think. We create a lower-level of awaken that targets only plants (but plants smaller than trees), doesn’t make them sentient, and basically just creates Plant-type animated objects. Unlike animated objects, the spell will only target one thing at a time and take a while to cast, but the result will be a real creature, not temporarily-animated ones the way animated objects does. And we’ll use lesser animate dead as a guide for balancing this, and slap the same spell level—2nd—on it.
###Lesser animate plant
- Components V, S, M (herbs and oils worth 25 gp per HD of creature created)
- Target non-creature plant touched
This spell functions like awaken except as noted. It can target only plants, but it can target any sort of non-creature plants, rather than just trees. The awakened plant has characteristics as if it were an animated object except it has the plant type. It has the usual mental ability scores for an animated object of its size, rather than scores each equal to 3d6. It is mindless, and must be controlled by the caster.
The caster can only control a limited number of such plants at a time. If all of the plants are tiny, the caster may control a number equal to four times her caster level. However, each small plant counts as two tiny plants, each medium plant counts as two small plants (four tiny plants), and so on, to a colossal plant counting as 32 tiny plants. Furthermore, the caster cannot animate any target that would consume more than half her control pool (so a colossal plant cannot be animated until the control pool is large enough to accommodate 64 tiny plants, at 16th level).
The caster may cease animating a given plant as a free action. When she does so, that plant returns to being an object, rooting itself as appropriate to the species if possible (if not, the plant will likely die soon after).
There, that should be a fairly good, consistent way to have druids in your campaign have plant minions around them as early as 3rd level. If any of your players want to know how, or want to do so themselves, this provides the means. Hope it helps.
