Extremely dark-flowered, Clematis 'Romantika' is a lovely, deciduous vine which is richly covered with 4 to 6 petaled flowers, 3-5 in. wide (7-12 cm), of a dusky reddish purple - almost black at first, with a velvety sheen. They slowly fade to dark purple as they age, and depending on the weather, the whole blossom can turn a deep red.