Culture
Grow in fertile, medium moisture, well-drained soils in full sun to part shade. Vining hybrids are best sited in locations where the flowering parts of the vine are in sun to part shade but the roots are shaded. Some light afternoon shade is usually beneficial in hot and humid summer climates such as the St. Louis area. Clematis vines need a trellis or other support on which to grow. Roots should be kept cool, shaded and uniformly moist. Root areas may be shaded with perennials, annuals or small shrubs. A thick root mulch is appreciated. Do not allow soils to dry out.
'Jackmanii Superba' is considered to be a pruning group 3 plant. It is usually pruned back hard to strong leaf buds approximately 8-12" from the ground in late winter. In the alternative, it may be given a light pruning in late winter followed by an additional trim after the first flush of bloom (pruning group 2). Plants need an adequate supply of nutrients during the growing season to support the rush of growth.
Noteworthy Characteristics
Clematis is a genus of over 250 species, most of which are woody to semi-woody deciduous vines climbing by twining leaf stalks or in some cases trailing over support, but in a few cases grow as freestanding or sprawling herbaceous perennials and small deciduous or evergreen shrubs. Most have flat, cupped or bell-shaped flowers. Some plants feature ornamental fluffy seed heads in autumn. Plants bear opposite, simple to compound leaves which are usually deciduous but sometimes evergreen. Compound leaves range from lobed to trifoliate to biternate to pinnate to bipinnate. Clematis are native to both the Northern and Southern Hemispheres including Europe, the Himalayas, China, Australasia, North America and Central America.
Cultivated plants are often divided into three groups based on pruning needs.
Group 1 – Flowers only on old wood (previous year). Prune after spring flowering.
Group 2 – Flowers on both old and new wood. Typically, little pruning should be done for woody-stemmed members of this Group. If cut to the ground or pruned in fall or spring, flowering will be reduced or delayed but not prevented.
Group 3 – Flowers only on new wood. Can be cut to the ground in fall or spring.
Genus name comes from the Greek word klematis which is an old name applied to climbing plants.
‘Jackmanii Superba' is considered to be an improved version to the long time garden favorite Clematis 'Jackmanii'. It features a more profuse bloom of more rounded and slightly larger flowers. This large-flowered, late-flowering hybrid clematis is a deciduous perennial vine that typically grows to 10-12' long. Velvet purple flowers (to 5" diameter) cover the vine with bloom from late spring to early fall (June to September). Flowers are followed by silky seed heads.
Problems
Susceptible to wilt/stem rot (can be fatal), powdery mildew, leaf spots, rust and viruses. Potential insect pests include aphids, vine weevils, slugs/snails, scale and earwigs. Watch for spider mites.
Uses
Clematis can be trained to climb a wall, trellis, fence, arbor, porch, lamppost or other stationary structure. They provides good architectural height and framework for small gardens. They can also be planted to sprawl over and through shrubs, scramble over old stumps or simply as a ground cover in conjunction with other flowering perennials. Containers.
Large containers.