It looks like this forum is inactive. I am by no means an expert but I can recommend a book. Roy E. Coombs - Violets: The History & Cultivation of Scented Violets
I found it very useful for research and history.

It looks like this forum is inactive. I am by no means an expert but I can recommend a book. Roy E. Coombs - Violets: The History & Cultivation of Scented Violets
I found it very useful for research and history.

Hello Melissa -

Many years ago I planted out 2 different Parma Violets into a woodland garden bed where they grew and flowered for several years. The soil was very well drained and organic. I do not remember the names of the violets, although I do remember one was white flowered and the other a lavender color. The winters in zone 5 are very long and cold, temperatures freezing and below with plenty of snow cover. I believe that the combination of very good drainage and reliable snow cover helped these plants survive, and possibly the fact that a lot of 'tender' plants that gardeners grow are actually much more cold and winter hardy when given ideal growing conditions. It did surprise me at first when I saw my Parma Violets growing and flowering in the garden after being left in the ground all winter, and wondered if anyone else has had the same experience.
I am not a sweet violet expert, but that was my experience growing them in the garden - the Parmas are much tougher and cold hardy than what is commonly thought or written about them. If I remember correctly, it was a dry hot summer that put an end to my outdoor Parmas. I have a couple of pots of Parma Violets growing now, and am living in a different location - maybe I will plant out a few young plants to see if I can get them through the year outdoors again - I will let you know!

Hi Melissa,

The Parmas will grow here in zone 7 year-round without too much trouble during winter. They flower a bit better and longer when covered with some kind of cloche, which seems to have more to do with increasing their humidity than it does with protecting them from outright cold. You are lucky to have 'Marie Louise'--that cultivar seems to have gone out of commerce here in the States in recent years, and plants that have reappeared in the last year or so under that name don't appear to be correctly identified (but I will be watching them closely this winter/spring).

The Coombs book is excellent and you might also enjoy Armand Millet and His Violets by E.J. Perfect, which includes a translation of Millet's Violettes, leurs origines, leurs cultures. I've run into a few downloadable out-of-copyright violet books on Google Books as well.

I have found Groves Violets in the Uk very helpful with questions about violets, in which they specialise. They sell all kinds of violets, including the Parma violets.