The colors of these two-toned pickles are most impressive when they're first made, but they taste just as good after the colors fade.
Wash 1 glass half-gallon jar with lid in hot, soapy water and rinse well.
Combine 3/4 cup water, vinegar, salt, and sugar in a saucepan and bring to a boil.
Meanwhile, fill jar halfway with either Vidalia or red onion slices. Add garlic shoot; cover with remaining onion slices, packing them with the back of a clean spoon. Leave 3/4 inch of space beneath the rim. Pour hot liquid over onions, covering them by 1/4 inch and leaving 1/2 inch of space beneath the rim. Place lid on jar and let stand until cool. Store in the refrigerator; serve within a week.