Barry Fretwell in his fine book, Clematis, reported that this clematis was named after the translucent, semi-precious gemstone, chalcedony, pronounced kal-said-ony. The large 12-20cm flowers are always double opening milky blue-mauve turning to ice-blue. Not a particularly vigorous vine, 2 metres at tops, it will make a good plant for growing in a pot as well as a good garden subject.
Pruning group 2


