Seeds Clematis pseudoalpina Rocky Mtn Clematis. This delicate, vine can be found trailing or climbing on vegetation. The four petal-like sepals are purple to white to violet and measure from 3/4 to 2 inches in length. This 10 ft. vine has spring blooming, almost translucent blue-purple flowers. Clusters of plumed seed in fall. Grows on trees & shrubs in forests & forest clearings. Needs water & likes good soil. Sow in fall or cold stratify & sow in spring. Hardy in zones 3 to 8.