I looked at all of the pictures and I've looked at pictures elsewhere. There seems to be a great deal of variation of color. I've only seen one up close and the color was vibrant. Most plants are not in bloom when they're purchased. How does one get the color they want?

On many plants, bloom color can vary according to climate, soil, amount of sunlight, water, etc. I have a Florida sieboldii that varies in color depending on if the bloom is early in the year or in the Fall. Don't know that there is any sure way to guarantee an exact color match.

Welcome to NGA, Deklan, and the Clematis forum.

I doubt there is any way to get the exact color you want from a clematis. It's a hit-or-miss chance.