Posted: 10/09/2015 at 20:08
Daisy, cuttings is always the way to go with salvias. you are right...it is not entirely hardy. Because they grow so quickly cuttings taken in summer will make large plants for the following summer so you could risk leaving it out once you have a cycle of cuttings and young plants.
Ironically many of these salvias...leucanthemum,,Amistad, Love and Wishes etc., are at their best in late summer and autumn. The colours just intensify.
So you could trim off long stems later in autumn and take into gh to save space.