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