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
Collect 500 butterflies
Have bought a total of 100 animals
Buy 25 garden expansions
Reach level 50
Bash 50 moles
Buy 15 garden expansions
Scare away 100 foxes
Have planted a total of 100 bushes
Have planted a total of 100 trees
Scare away 100 wolves
Gather 1M Gold
Gather 100k Gold
Grab gold 500 times from the Loot Hero
Scare away 100 bunnies
Buy 5 garden expansions
Gather 10k Gold
Collect 10 ladybugs
Grab gold 100 times from the Loot Hero
The Loot Hero bashed a mean critter!
The Loot Hero have appeared 5 times
The Loot Hero has appeared!
Reach level 10
Trash 10 items
Scare away 500 birds
Have planted a total of 100 plants
The Loot Hero have appeared 25 times
The Loot Hero have appeared 50 times
Grab gold 1000 times from the Loot Hero