Salvia Indigo Spires (rear) with pink Garvinea at frontThis 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, and was found growing in the Huntington Botanical Gardens in the USA. Its height is around 1.5 m and it likes a sunny position. It is sensitive to severe frost. 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. It is particularly stunning when grown with lime-hued foliage plants. 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 autumn, in mild areas, it can be cut back hard. Leave this till late winter in frosty regions.
Salvia Mysty, a compact version of Mystic SpiresAnother cultivar, 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 a bit shorter! I think overall, 'Indigo Spires' is the better plant of the two. A recent cultivar called 'Mysty' (pictured above) is said to be a compact version of 'Mystic Spires', growing only to 30 cm, and so far, it seems to be a true low grower.
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