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
Identify all the plants
Complete a full playthrough without using the hint button
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
Murder Burbidge
Visit 20 map locations
Recover from Rising Dread
Identify 10 plants
Solve your first clue card
Pet Hellebore 13 times
Handle your first customer