Brunnera 'Jack Frost' Feb 12, 2014 Sky blue, forget-me-not flowers and leaves with a netted silver overlay. 'Jack Frost' is absolutely stunning from early spring to fall. One of the showiest and most worthy plants to come along in a decade, hence Perennial Plant of the Year for 2012. Hardy in zones 4 to 9, and a mounding habit reaching 14 inches high, 24 inches wide and a flower height of 17 inches. Share This Article