This magnolia tree, along with other species, had started to open its' blossoms a bit prematurely thanks to mild and sunny weather in February this year. You can clearly see the cold killed off the flower that has turned brown; essentially frostbite. The tree has plenty of flowers to produce as indicated by the other large fuzzy flower buds. Every year it seems that some species gets nipped by late winter/ early spring deep freezes and the blossoms die. All flower buds on a single plant are rarely lost, especially depending on the location of the the plant. This year several species succumbed to the freezing temps; even daffodils are laying on the ground. Nothing practical can really be done to try and prevent this. Forsythia, some magnolias, and lilacs are pretty typical plants to get spring frostbite.