Well, if you don't know what it is then it's hard to say. Many trees don't mind if their buds freeze. Are these trees in container, or in the ground? If they are in the ground chances are they'll be fine because they would have to be a variety that can handle your climate. If they are in containers I assume you'd just bring them in. Can you post some photos?

Unless you are going to take really dramatic steps (like covering the tree and heating overnight) then you'll probably have to just wait and see if the blossoms are damaged by the cold. Hopefully you have trees that are well suited to your climate, and therefore most of the time the blossoms won't be killed by frsot because the trees will bloom at an appropriate time of the season.