Identification: Curious Clematis Convertion

Please help with my confused plant.
Two years ago I bought a fine clematis called 'Mrs.P.T. James'. It was hybridized by Mr. James, on Salt Spring Island where I purchased it.

It bloomed one bloom, the usual double light blue, and then got a clematis wilt, so I cut that stem right down to the base. That same year (last year), it sent out a healthy shoot. Today, it is blooming something quite striking and amazing -yet not the colour of bloom the plant is supposed to have. It is still a double bloom, but quite violet in colour, with a lighter strip in the center of the ruffled, pointy petals.

Please admire the photo I took ( darker flower), and the other photo I pulled from the internet,

( lighter) and help me understand what & how this happened.

 

Ask the nursery where you bought it - it may be that the purple-flowered plant is the rootstock they graft onto.

 

I called Foxglove Nursery. The person who answered the phone had no idea about clematis plants.
Although, he did say they are not grafted. But, frankly, he admitted to not knowing much about clematis plants.....

 

Ask to speak to Mr James, whenever he's available!

 

It might just be a little stressed. Description at Clematis on the Web says the colour is violet-blue so the observed colour is not excessively different than the expected hue. Wait till next year and see if it reverts to a more blue colour.

Production of grafted clematis is rare these days, and even when used the grafts are planted deep when potted up such that the cultivar develops its own roots and the nurse rootstock dies off.

 

Structurally similar, just a little different in coloring - could still be the same variety showing variation with conditions. Flowers may even become less dark with age of individual bloom, or progression of season. Many kinds of blue, purple etc. flowers vary like that, for instance blue forms of Geranium wallichianum are more purple in warm weather and more blue in cool.