This is one of the classic, versatile and indispensable salvias, with long inflorescences of violet-blue flowers over a very long period, from late spring until late autumn. It is a hybrid of Salvia longispicata and Salvia farinacea. Its height is around 1.3m and it likes a sunny position. It sprawls a bit so may need support from cradle stakes or other plants. It associates well with roses and cottage-style perennials such as campanulas, perennial phlox, purple coneflowers (Echinacea purpurea) and Marguerite daisies, but goes equally well with more semi-tropical plants such as cannas, cleome and dahlias. It mingles with basically any colour of flower or leaf, on the hot or cool side of the spectrum. As it flowers for so long, it can be tidied up every so often by removing one large stem at the base of the plant. Some gardeners cut it back drastically a few times during the growing season, which is another approach to pruning. It can also be deadheaded occasionally to remove the elongated spent spires. In late winter, it can be cut back very severely. A new compact form, which is very similar, is called 'Mystic Spires', and is a bit shorter and more upright. However, this can grow rather wide, even though it is shorter! I think overall, 'Indigo Spires' is the better plant of the two.