Perennial vines add charm and beauty to the landscape, are great at camouflaging fences and old buildings and create stunning vertical accents.
Some of the best perennial vines are the many varieties of clematis that are hardy on the Prairies. Some retail outlets sell clematis that are not hardy in zones 2 and 3, so care is re-quired before purchasing.
The hardiest clematis varieties are the small flowered clematis alpina and clematis macropetala.
Both have small flowers and dainty foliage on long climbing woody stems that are seldom killed by winter’s cold temperatures.
The old growth leafs out again the following spring and the plants only need pruning to control their shape and size. These hardy clematis have a heavy flush of early bloom on old wood in May and June, and then they bloom sporadically throughout the rest of the growing season.
C. alpina tangutica, the oldest and best known of the hardy clematis, has yellow lantern-shaped flowers and is consistently hardy, even in zone two.
C. alpina Pamela Jackman has dark purple blooms and C. alpine Willy sports white flowers, while C. alpina Francis Revis is a blue variety. All are closely related to C. alpine tangutica.
Another type of clematis, C. macropetala, is equally hardy and some of these plants have been crossed with C. alpina varieties to create new clematis varieties that are hardy with other desirable characteristics.
Frank Skinner did much of this plant breeding work decades ago. Many C. macropetala have blooms that are almost double. The centre of each flower has a fluffy bunch of staminoids surrounded by colourful petals.
C. blue bir and C. Rosy O’Grady are two examples. Blue Bird has pale blue flowers while Rosy O’Grady produces dusty rose blossoms.
My C. Rosy O’Grady completely covers a trellis beside the garden shed and blooms profusely in early summer and sporadically for the rest of the summer.
Like many other hardy clematis, it also has attractive silky plumes later in the season that are actually the seed heads.
Other hardy clematis well worth having in the garden are the large-flowered hybrids, many of which contain some alpina or macropetela parentage. These vines die back to the ground each winter but put forth such vigorous growth in the spring that by late June or early July, they will be in full bloom.
The best known hybrid hardy clematis is C. Jackmani, the dark purple variety whose large single flowers are produced from late June until early September. C. Ville de Lyon, which has carmine red blooms, and C. Ernest Markham, which sports magenta-red flowers, are two other varieties.
C. Polish Spirit is another purple-blue variety, quite similar to C. Jackmani, but some gardeners find it more winter hardy than C. Jackmani. The blooms of Polish spirit are darker coloured and smaller than those of C. Jackmani.
Sometimes varieties of C. Montana are offered for sale but they are borderline hardy. One good example is C. Montana Nelly Moser, whose large single blooms are spectacular and produced on both old and new wood.
Unfortunately the vine usually dies back to ground level every winter, if it isn’t winter killed, and so the early bloom on old wood rarely occurs in our area.
By the time new wood has developed enough to produce bloom, the growing season is over.
Clematis vines are sun loving plants and a southern exposure is ideal, although I have seen wonderful specimens planted against east-facing and west-facing walls. They like lots of water but the roots must be provided with good drainage and be kept cool by having plants placed in front of them to shade the root zone from the blazing sun.
A trellis of some kind must be provided for clematis and they require a bit of training until they get established on the support. Given the right location, water and support, a hardy clematis vine will provide years of enjoyment in your garden.