Rosa Mundi is an ancient striped gallica rose - rosa gallica versicolor.  A good friend gave me this rose many years ago and has proved its hardiness by surviving this long. It has not increased in size, but it returns to bloom every June.  It is listed as hardy to Zone 4, so why hasn't it thrived?  If I am honest I must assess the planting site. Although it is said to be tolerant of some shade, I…