Eugene de Beauharnaise
This very compact China is well suited for pot culture.  The brilliant purple blooms have a wonderful fragrance and  form.  The purple has a depth of shadings.  In full sun they can burn so it needs a little afternoon shade.  It is a shrubby plant though small.  For me it has some tendency to get blackspot but it's worthwhile anyway because it's really pretty and has great rebloom.  Bred by Hardy in France in 1838, it is rated as hardy from zone 7.