Here is the full list of all 19 Gardenia achievements.
1st Trash pile cleaned
Uncle Fluffy hut is fixed
Veirdest quest for Mr. C completed
Kim is your friend now!
Woody quest completed
You found all ancient coins
You collected all 10 gnomes!
You managed to stop the pollution of the island!
Foxy is your friend
Romance path with Foxy
100 gold coins earned
300 gold coins earned
700 gold coins earned
1000 gold coins earned
10 plants planted
100 plants planted
300 plants planted
You made at least 3 different tools
You crushed 100 snail shells