Wood element wizards, phytokineticists, fey this that and the other...care to define what you're after a little more? Most classes have at least one option that might be defined as nature based, many have several.
Plants, huh? There are verdant bloodlines for sorcerer and bloodrager, and arcanists and eldritch scion magi can get those too. And sorcs can pick up the wildblooded variant.
Oracles can get the wood mystery, shamans a wood spirit, and spirit guide oracles can get either or both. Clerics and warpriests of woodland gods exist.
Horticulturalist alchemists and cultivator bards and witches with plant-themed patrons (there's more than one of those) are all things that might appeal to you.
Any archetype for ghorans or leshies will be plant-themed.
Plus the stuff I started mentioning above. No idea whether you want plant pets or summons, or plant battlefield control, or wooden weapons, or spore-based mind control, or plant (semi-) shapeshifting, or even plant-themed blasts, but all of those are possible.
You might look at a treesinger with the summon plant ally feat, or a horticulturalist perhaps with the tanglefoot bomb discovery first up then.
Herbalist alchemist is a plant, its main weapon is to throw exploding seeds and it adds druid spells to the alchemist extract list.
Its also a leshy so it is pretty good at growing other little leshy friends in that is you bag.
bramble brewer alchemist
Whatever that half-elf summoner archetype is.
The Symbiosis Psychic Discipline is pretty cool. It's sorta 50/50 with plants and animals, and your early bonus spells are all animal-based, but there's a lot of cool plant things there, too.
Grasping vine archetype shaman get a plant based spirit animal, uses of speak with plants spell as an SLA, and can eventually do a wild shape style option to turn into plants for min/level. They also add a selection of plat related spells to their list.
You can also pick the nature or wood spirits for more plant-y-ness.