Clematis ‘Purpurea Plena Elegans’ - An extraordinary and intriguing double-flowered clematis in a rare smokey reddish purple with a paler centre where the backs of the petals, still tightly furled, are revealed. Flowering very generously from July to September, the extra weight of the double flowers demands good stout support. First seen in about 1900. Prune hard in spring. 3-4m (10-13ft).