Bridal Wreath Spirea ShrubsBridal Wreath Spirea Shrubs for Sale Online Like other spireas, Bridal Wreath Spirea Shrubs bloom in late Spring to early Summer, sometimes before the leaves come out. When in bloom, Bridal Wreath Spireas create a cascading waterfall of white, with clusters of small flowers all the way down its arching stems. When cut, those stems can easily be shaped into bridal headdresses.