Seeds from Clematis alpina Clematis Alpina clematis is one of the earliest clematises to bloom, in early May. It bears relatively small but delightful nodding, blue or pink bell-shaped flowers, 1 – 1. 5 inches in diameter, in a great variety of colors. Grows better in shade than in sun. Best suited for a north-facing, cool, shady position. Unless it starts to look scraggly, it rarely needs pruning, as it flowers on old growth. Grow in fertile, well-drained, acidic soil with abundant organic matter. Hardy zones 4-9.