Start by taking out any dead, diseased, or damaged wood. Then follow the pruning directions below, depending on when your clematis blooms.
Pruning group A (or 1)
A is for After bloom
Includes: Species that bloom in early spring, such as C. montana, C. armandii, or C. macropetala
When and how to prune: Don't prune until after the flowers are finished. Flower buds were formed the previous year, so pruning before they flower means no flowers that year.
Pruning Group B (or 2)
B is for Before bloom
Includes: Species that bloom in late spring/early summer, including most large-flowered types
When and how to prune: In spring, cut back to a set of live buds, about a third down from the top. Hard-prune (to about 12 inches) for the first two years after planting to develop a strong root system.
Pruning Group C (or 3)
C is for Cut back hard
Includes: Species that bloom in summer/early fall: C. viticella, C. tangutica, C. virginiana, C. texensis, C. crispa
When and how to prune: In early spring, cut every stem to 12 to 18 inches or so.
Mail Order Sources for Clematis
Brushwood Nursery, Unionville, PA; 610-444-8083, gardenvines.com
Chalk Hill Clematis, Healdsburg, CA; 707-433-8416, chalkhillclematis.com
Completely Clematis, Ipswich, MA; 978-356-3197, www.clematisnursery.com
Garden Crossings, Hudsonville, MI; 616-875-6355, gardencrossings.com
Joy Creek Nursery, Scappoose, OR; 503-543-7474, joycreek.com