I am really losing my mind because I know I JUST saw this project somewhere and I can not remember where...again! Sorry, it's a great, cute, EASY idea!
I took a sponge and cut it into a Heart Shape and one piece into a skinny rectangle.
I set out green, green-yellow, and light green paint and had "Indy" dip the heart in and stamp in three times on the paper in a clover shamrock pattern and then used the rectangle for the stem. You could just draw the stem. That's it. So simple and cute!