Chapter 5You will find this plant in chapter 5 after entering the boat house.
1.Add soil
2.Add Oscilette seed
3.Add water
4.Take the plant up to the building above and place in it's spot next to the phonograph
5.Add the Meadows Bliss song to the phonograph, it should be the middle one on the left side next to the window with the white label green edges
6.Start the phonograph with the lever and the music will begin and the plant will grow
If you need more help with this you can see my video below: