General Characteristics: Clematis may be planted and trained to cover walls, trellis, posts, fences, arbors or to cover rocky sites. It will need support. Prefers a rich, well-drained soil with a pH of 5.6-6.5. Clematis do best in neutral or slightly alkaline soils, but they are somewhat adaptable. If you have very acid soil, try to add some calcium when you plant. If you want to grow really good clematis you should incorporate a little lime in the planting holes. Roots should be planted in a cool moist environment, while the vine itself should be in the sun. Root area should be protected. They require 1" of water a week. 'Jackmanii Alba' has double white flowers are borne on previous years wood. Single white flowers are produced on new growth.
Clematis Repeat Blooming: (Group B)
These are early double and semi-double mid-season cultivars. They bloom mid June and if healthy they will bloom again around September in a smaller show of color. These bloom on the new growth that is produced from old buds produced on stems from the previous season. If they are pruned to the ground, they will bloom, but will miss the big and beautiful early flower period. Remove dead and weak stems in February or March, leaving the best of last year's buds. Once they finish blooming, cut the plant back to 16" to encourage new growth for fall flowering.