Mary Anna, Sharon M and Daisyboo9 here is how I made the row:
I draw a chubby heart shape ; repeated it on double side fusible web 3 times for each shamrock. Stems were cut from fusible leftovers between heart shapes. Fused hearts on a 4.5 strip of background fabric and machine appliqued.
I set the pieces at random - distance between each other, position and distance from top/border - to get movement.
Thanks for asking.
PS: I fuse the web on fabric before piecing the shapes ... :)