In this case I would not blazon the roundels vert as pommes.  Pomme means "apple."  As a pomme, the roundel is appropriately emblazoned as a sphere rather than a disk.  But these green circles are not spheres, they are round holes in another object.  An apple may be pierced, but something cannot be pierced of an apple.

Try doing the motto in Latin…makes it sound more noble.  :mullet:

How about the motto: "When the cat’s away, the mice will play"?