Here is the full list of all 29 Plantera achievements. It takes around 6-8 hours to unlock all of the achievements on Windows.
The Loot Hero have appeared 50 times
Reach level 100
Bash 50 moles
Scare away 100 wolves
The Loot Hero have appeared 25 times
Have planted a total of 100 plants
Have planted a total of 100 trees
Collect 500 butterflies
Scare away 500 birds
Scare away 100 foxes
Scare away 100 bunnies
Reach level 50
Grab gold 1000 times from the Loot Hero
Have planted a total of 100 bushes
Have bought a total of 100 animals
Buy 25 garden expansions
Collect 10 ladybugs
Grab gold 500 times from the Loot Hero
Gather 1M Gold
The Loot Hero have appeared 5 times
Buy 15 garden expansions
Gather 100k Gold
Grab gold 100 times from the Loot Hero
The Loot Hero has appeared!
The Loot Hero bashed a mean critter!
Trash 10 items
Reach level 10
Buy 5 garden expansions
Gather 10k Gold