My favourite nursery's website says "very large bluish purple flowers", and you need to know that it's not hardy -
"Full Sun - if outside
Greenhouse or Conservatory - Not the sort of plants to be grown outside where there are likely to be frosts. These plants need to be grown in a conservatory or cool greenhouse or at least brought inside for the winter - loam based potting compost, full light, shade from hot sun "

I'm trying one too - it's showing some growth but no flowers as yet.