Princep Liquid Herbicide works as a pre-emergent herbicide to kill a variety of grass and broadleaf weeds. It is not labeled for blueberries. Can you tell us more about what you are treating for on or around blueberries so that we can offer you another product that will be effective?
According to the product label, the manufacturer does not recommend folks use Princep Herbicide on Zoysia that far north. If you are looking for a pre-emergent for broadleaf weeds that can be used on Zoysiagrass, Surflan Pro would be an excellent option.