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