The English Rock Garden, the magnum opus of the great gardening writer, horticulturist and plant collector Reginald Farrer, is an indispensable A to Z guide to alpine flowers. When he finally reaches V, Farrer writes: ‘Viola brings this alphabet to the last great dragon in its path.’ But rather than offering fire-breathing terror, he presents a family of flowers containing both beauties and ‘dull and dowdy species’. There are between 400 and 500 species in the viola family. The sweet violet, while lacking the dark mystery and beauty of its cousin Bowles black, was associated with Aphrodite and became a symbol of both Athens and fertility, which evolved into a Scots tradition of violets being presented to brides on their wedding day in the Athens of the North.