'Jackmanii Superba' Clematis is a deciduous vine with prolific blooms and a vigorous growing habit. Large flowers are star shaped, violet with yellow centers and cover the vine starting in late Spring. After first flush of flowers, prune back top 1/3 of vine to encourage a second late summer bloom. Clematis prefers moist soil and shaded roots, a layer of mulch in the summer is key for this plant.