Here is the full list of all 18 Strange Horticulture achievements. It takes around 8-10 hours to unlock all of the achievements on Windows.
Bring about the Redemption
Take control of the Servant
Complete a full playthrough without using the hint button
Murder Burbidge
Identify all the plants
Complete the game
Perform the ritual
Save the Sisterhood
Create an Elixir
Open the secret drawer
Find a Bryer's Disc location
Activate the viewing device
Visit 20 map locations
Pet Hellebore 13 times
Solve your first clue card
Identify 10 plants
Recover from Rising Dread
Handle your first customer