June is still a traditional time for people to get married, and throwing rice at the couple was once a wedding staple. The practice is still performed on occasion, though throwing birdseed has gained popularity. In either case, once all of those little baggies are bundled with rice or seeds, they can be charged with the magic of fertility and prosperity, which is what they are supposed to symbolize.
When the bundles are created, they are usually gathered together in a basket, and this is where they can be blessed. Holding your hands over the basket, visualize pure white light streaming into the basket, bathing the bundles in magical power, and say:
Delicate bundles, you will be;