Here is the full list of all 36 Botany Manor achievements.
Grow the Windmill Wort
Grow the Fulguria
Grow the Phoenix Of The Forest
Grow the Pixie Tears
Grow the Wolfglove
Grow the Sapphire Gloom
Grow the Nightfall
Grow Brook Chalice
Grow the Cradle Fern
Grow the Springdance Shrub
Grow the Oscilette
Grow the Fool's Emerald
Flush The Toilet
Connect all the pipes
Create a faulty mix of chemicals
Find the secret priest hideout
Open Grandmother's secret vault
Open the letter lock
Fix the orangery staircase
Throw a flower in the compost
Go to the top of the tower
Find a way across the pond
Germinate the Ash Plume seed
Inspect a duck
Sit down on a seat
Play The Harpsichord
Shake a locked door
Reach the end of the game
Inspect all the ducks
Complete every page in the Herbarium
Signal S.O.S. on the telegraph
Place a plant on every saucer in the Flower Room
Sit on a seat for one minute or more
Take a picture of a flower that's not the Fulguria
Grow the same plant three times or more
Inspect Arabella's paintings