you need touchscreen
click the plant as usual, move it to a spot with little enough light and then use touchscreen to place the plant wherever you want
I think it works because when you press with your finger the plant immediately goes to the spot and the game probably just checks to see if the plant was in sunlight before it was placed
example (1st time shown what happens normally, then with the glitch): https://drive.google.com/file/d/1JtVMzfNljLQkx5YePUYNAqd5F_fc9Phb/view?usp=shari...