The genus viola has around 600 species which includes dog violets (commonly called Johnny Jump-Ups because they self-seed and spread everywhere), wild pansies and sweet violets. Some of them are perennial, others annuals. Pansies are a cross between wild violets (viola lutea) and Viola tricolour.
The origins of the violet are not known although it is thought they may have come from North Africa. Of all the violets, the Parma violet is probably the least well known although it was a different story a hundred years ago. Bunches of Parma violets were sold on street corners and flower shops across Europe. This was mainly because of their perfume; the chemicals released temporarily disable the sense of smell. Carried as a nosegay in a time when streets were often open sewers, or sat at the theatre with many other people who rarely bathed, the advantages of this flower becomes quite obvious.
In the eighteenth and nineteenth centuries, Toulouse was the main supplier of Parma violets in Europe. After WW1, the flower fell out of favour. Many of the old species of Parma violet are believed to now be extinct, although it is hoped that one day some may be rediscovered growing in gardens in France.
A family in Valencia has been growing Parma violets for over fifty years and although Parma violets are not drought resistant, they are easy to grow and will flower twice a year, in spring and again in autumn. They need partial shade or just morning sun, and will form a large clump. Unlike the wild violet, they are not invasive and spread by runners rather than by the seed.
Parma violets are usually double flowered and the blooms are held 12-15cm above the heart-shaped foliage. Species of Parma violets are available from some online specialist nurseries. Old varieties to look out for include Duchesse de Parme, Marie Louise, Gloire de Verdun, Parme de Toulouse and D'Udine. Viola Comte de Brazza was the only white Parma violet in existence in 2000, hopefully more heritage species have been discovered since.