If you like history and you love clematis, you can learn a lot about Polish history studying the names of the hybrids of Brother Stefan Franczak. But like many other clematis breeders, he also named hybrids after family members. In the case of this truly unique and thoroughly showy clematis - both in size and color - 'Kacper' (pronounced kăs-per) was named after Franczak's father. (One of the Three Wise Men was "Casper", too.)
In the gallery of Franczak hybrids - crowded with masterpieces - 'Kacper' is a true achievement of form and function. Officially it is said to bloom from May-July and September-November, but in my home garden it never stops. Although considered "early", as the large-flowered clematis go it can start later (early June), but is never completely out of bloom until the first frost of late autumn, producing new wood as it flowers, new wood that matures quickly and flowers promptly. What makes this possible is the heavy substance of the sepals, allowing the current branch of flowers to last long enough that the next bouquet is ready when earlier flowers finally fade.
This year, the often 20-25cm diameter flowers hit a new high both at home and at work, 27.5cm! That's 11 inches in the USA, and others have reported even larger 'Kacper' blossoms. Combine flowers of this size with its bold color and you have a plant that gets noticed. The sepal edges can be crimped or crisped, adding interesting texture to the expanse of rich color. Described as "deep violet", it opens as a solid color with a bar usually, but not always, developing as the flower ages. (Author's Note: in some places "violet" implies blue, but by most definitions "violet" is a tint of purple falling in the red-influenced range of that color. In the US, purple is more blue, violet is more red.)
Mature vine height is 2-2.5 meters, and it responds well to pruning, be it deadheading of spent flowers, "hard" deadheading to take off lanky growth when spent flowers are removed, pruning by ⅓ in late winter to encourage earlier blooms, or even hard-pruning in winter. At the Rogerson Clematis Garden, where our three specimens of 'Kacper' are planted in a triangle around the subshrub Caryopteris 'Snow Fairy' (variegated bluebeard), we groom for plant health by removing dead stems whenever they appear, but the three plants are pruned to different lengths, to enhance the likelihood of continuous bloom. They are deadheaded throughout the season.
Do not be intimidated by the vividness of the color. We have paired it with the variegated bluebeard to act as a filler for the fabulous flowers, but often 'Kacper' has its own ideas. It goes boldly into stands of Oh Henry! lilies (an Orienpet seed strain by Judith Freeman), lolls into the wonderfully upright grass Miscanthus 'Gold Bar' with its myriad bright horizontal stripes, and this year blended with a violet and gold tall bearded iris that flowered late due to a cold wet spring. The color marries well with the English rose GOLDEN CELEBRATION 'Ausgold'. Because of the strongly upright carriage of the flowers, 'Kacper' also serves admirably as a groundcover in concert with Geranium 'Rozanne'.
All-in-all it is quite wonderful how durable and dominating 'Kacper' can be whether alone on an arbor or combined with plants of equally bold foliage or flower color.