A blade arrangement is provided for a gas turbine, in which blade leaves, having a leading edge and a trailing edge and also a pressure side and a suction side, are assembled sealingly with platforms configured as separate components. A peripheral sealing arrangement is provided between the blade leaves and the associated platforms, which seals off an interspace between the blade leaves and platforms against hot gas flowing around the blade leaves. A directed site-dependent supply of cooling air for purging the sealing arrangement is provided on a side of the sealing arrangement which faces away from the hot gas. A method of operating the above blade arrangement is also provided. The method includes supplying cooling air for purging the sealing arrangement at a pressure which decreases from the leading edge of the blade leaves to the trailing edge.