One of the more spectacular flowering vines available is the clematis. Clematis have a wide hardiness range dependent upon the species. Finding the right clematis vines for zone 3 is essential unless you want to treat them as annuals and sacrifice heavy blooms. United States Department of Agriculture zone 3 plants need to be hardy through weather temperatures of -30 to -40 degrees F. (-34 to -40 C.). Brr. Cold hardy clematis do exist, however, and some even can withstand temperatures down to zone 2.
Cold Hardy Clematis
If someone mentions clematis, even novice gardeners usually know what plant is being cited. These vigorous vining plants have several pruning and blooming classes, which are important to note, but their hardiness is another trait required when purchasing these lovely flowering vines. Clematis vines in cold climates should be able to survive the extreme temperatures that often occur. Extended winters with excessive cold temperatures can kill the root system of any plant that is not adapted to that level of cold. Growing clematis in zone 3 starts with picking the right plant that can acclimatize to such long chilly winters. There are both hardy and tender clematis. The vines are also classed by their blooming period and pruning needs.
- Class A – Early blooming clematis rarely perform well in zone 3 because the soil and ambient temperatures won't warm up enough for the plant's bloom period. These are considered Class A and only a few species can survive in zone 3.
- Class B – Class B plants bloom off of old wood and include huge, flowering species. Buds on the old wood can easily be killed by frost and snow and they rarely provide a spectacular color show by the time blooming should start in June.
- Class C – A better choice are the Class C plants, which produce flowers off new wood. These are pruned to the ground in fall or early spring and can start blooming in early summer and continue to produce flowers to the first frost. Class C plants are the best option for clematis vines in cold climates.
Hardy Zone 3 Clematis Varieties
Clematis naturally like cool roots but some are considered tender in that they can become winter killed in extreme cold. There are, however, several zone 3 clematis varieties that would be suitable for icy regions. These are primarily the Class C and some that are intermittently called Class B-C. The truly hardy varieties are species such as:
- Blue Bird, purplish blue
- Blue Boy, silvery blue
- Ruby clematis, bell-shaped, mauve-red blooms
- White Swan, 5 inch (13 cm.) creamy flowers
- Purpurea Plena Elegans, double flowers are lavender blushed with rose and bloom July to September
Each of these are perfect clematis vines for zone 3 with exceptional hardiness.
Slightly Tender Clematis Vines
With a little protection, some of the clematises can withstand zone 3 weather. Each is reliably hardy to zone 3 but should be planted in a sheltered southern or western exposure. When growing clematis in zone 3, a good thick layer of organic mulch can help protect roots during harsh winters. There are many colors of clematis vines in cold climates, each with a twining nature and producing vigorous blooms. Some of the smaller flowered varieties are:
- Ville de Lyon (carmine blooms)
- Nelly Moser (pink flowers)
- Huldine (white)
- Hagley Hybrid (blush pink blooms)
If you want truly stunning 5 to 7 inch (13-18 cm.) flowers, some good options are:
- Etoille Violette (dark purple)
- Jackmanii (violet blooms)
- Ramona (bluish lavender)
- Wildfire (amazing 6 to 8 inch (15-20 cm.) purple blooms with a red center)
These are just a few of the varieties of clematis that should perform well in most zone 3 regions. Always provide your vines with something on which to climb and add plenty of organic compost at planting to get the plants off to a good start.