We’ve all heard about the “sweet spots” in this game in order to make two flowers grow at once. Well below are screen shots of each step. You want to work from right to left.
Notice the blade of grass inside the red circle and how the can hangs over slightly to the right. Of course there is a little leeway to the left or right but not much. Try to position it accurately.
If you positioned it correctly, it will look like picture #2.
Notice where the can is inside the red circle and how close the stalk is. There is a tiny bit of space in between.
And if you do it right, it will look like the 4th picture. And viola! Now you’re an expert!