Today I bought a plant named Viola odorata 'Katy', it's a rose pink, single flower but I can't seem to find any information on it. Is Katy a registered name?

I've been growing Sidborough Pink for a while, although it's disappeared for the winter, again I can't find information on this cultivar. It's also produced nothing but cleistogamous flowers for a year. It's current residence is a cold greenhouse, any information?

Another one I can't find much on is V. bubanii, anyone care to share?

Many violets do, indeed, change their petal mood depending on day length, like Tom says - long days promote cleistogamous flowers (though you can get a few petalled flowers on almost any violet in cleitso mood, now and then).

Viola bubanii:
One of the little charmers from the Pyrenees, occupying a similar niche to V. cenisia (eg.) in the Alps. I was disappointed not to see it on my trip to the Pyrenees a few years ago (but I was pleased with the species I did see, and the friends I went with). It grows both in high pastures and rockier crevices.
It can be bought from Kevock Garden, near Edingburgh (http://www.kevockgarden.co.uk/). You could contact them to see if, from their experience of growing it, they can answer any specific questions you may have.
I'd also contact the Jardin Botanique du Tourmalet (http://www.afleurdepau.com/65/Tourmalet/Site.htm).
For a photo and a little description, try the link below.

The greenhouse has filtered light as it's still bubble-wrapped on the inside but last year it was growing in outside in partial shade (morning sun only). We don't have any heating, let alone lighting in there ;). The other Violas have similar conditions throughout the year and only the Sid. Poppet and koreana don't produce petals. I'll try and find a different site for them this year to see if that makes a difference.

Thanks for the links Mike I'll have a poke about and see what info I can glean about bubanii. :)

Anyone know about Katy?

Baa

Sorry - yes - 'Sidborough Poppet' - I forgot...

I have only grown this cultivar once, years ago. I bought it from Westacre Gardens in Norfolk, and it soon died on me (without flowering). The demise of the plant possibly reflected my cultivational ineptitude at the time -- I do not want to cast aspersions on West Acre!

You know, I still don't know for sure the origin of this cultivar. If I had to have a stab, I'd say Viola riviniana; and if pushed 'Purpurea Group'. There is a tricky taxonomic point here in that if I am basically right, since I do not know the formal definition (in terms of size ranges of leaves, eg.) for the 'Purpurea Group' cultivar group, 'Sidborough Poppet' may fall within it or outside it. Anyway, all I can do is chew the point with you generally - sorry.

I don't know about V. odorata 'Katy', though I would try checking for cultivars by that name as spelled in other languages, eg. 'Katja'.
I have a worry, though, since there is an African Violet called 'Katja' or 'Rhapsodie Katja', etc. (see link).
Another possibility (clutching at straws)... Morris May, who is a commercial grower of various members of the Viola genus, has a relation called Katie...

Mike

Sidborough Poppet flowered well this year (just to prove me wrong) and while it's colouration and flower shape is very similar to V. riv. Purpurea Group, it's so much tinier in comparison. I wonder if it might be sterile because all the seed I've collected and those that must have self sown have never germinated.

I think you may be right on Katja Mike, it lists that name on the label as well as Katy.