Clematis, Queen of the Climbers

To hide an unsightly fence, adorn a stark chimney, or drape over a porch roof no vine beats the versatility and beauty of a clematis, the queen of the climbers, and no garden should be without one. The expanse of varieties – some flowering from early spring through to the first frost, double flowers, single flowers, white, pink, lavender, striped, iridescent, old cultivars, new hybrids – offers a vast menu of choices. And forget all that hype about difficult cultivation and confusing pruning requirements. Follow a few simple guidelines and your climbing clematis will reward you with a sparkling burst in early spring, followed by a second flush in fall if you choose an early flowering variety, or a dazzling display for months if your choice is an everbloomer.

Aside from differing pruning requirements, all 200 species of clematis have the same cultural needs. They thrive in well-drained, slightly alkaline soil that’s rich in humus, a regular feeding program, and cool roots. Most want their faces in the sun, although a spectacular clematis was spotted spilling a profusion of creamy white flowers over the roof of an outbuilding in the dense shade of a wooded golf course. So less than perfect sun conditions don’t seem to diminish their blooming exuberance, but they must have their roots shaded and cooled with a 3” layer of mulch or an underplanting of low growing shrubs. Clematis are heavy feeders and should be fertilized once every six weeks during the growing season starting in spring when the buds are 2” long, and regular watering is appreciated, but slack off in the winter when the plants are dormant; they are not fond of wet feet and winter watering encourages root rot. Aside from cool, well-drained roots, the clematis isn’t fussy about cultivation, and the only disease that seems to plague the species is clematis wilt, a fungus that attacks newly-planted large-flowered varieties, causing the youngest leaves to droop. To minimize the chances of contracting the disease, plant your new clematis 2” deeper than the nursery pot level. Occasionally you will find the late summer bloomers sprinkled with powdery mildew, but that fungus can generally be controlled with a fungicidal spray such as benomyl. Now let us address the pruning needs.

For convenience, all clematis have been categorized into three groups, based primarily on bloom periods, and this categorization determines pruning requirements. However if you prune “incorrectly” – that is, if you cut it back at the wrong time of year – you will not kill the plant. You will only reduce the number of blossoms the first season, a small price to pay for the error. The first of the three groups, Group A encompasses the early flowering species and their cultivars, those clematis that fall into the armandii, alpina, and montana species groups. These species need little or no pruning, but if the plants threaten to take over, cut them back right after flowering in May or June. Group B clematis encompasses the early large-flowered cultivars, and they flower on new short stems sprouting from last season’s wood. This group should be pruned in late winter or early spring before the new growth appears. Start pruning them at the top and work your way down. The final group, Group C, is comprised of herbaceous and late-flowering varieties which produce their blooms on the current year’s growth, and this group of clematis which includes the popular C. ‘Jackmanii’ should be pruned hard in the late fall or early spring. If left unpruned, these climbers can grow out of control so be sure to cut them back to two strong sets of leaf buds as close to the ground as possible. For this group you can start pruning at the bottom of the plant and work your way up. As a general piece of advice, all clematis should be pruned hard, back to a healthy pair of leaf buds, the first February after planting. If you neglect this exercise you will wind up with a bunch of bare trunks at the base and a tangled mess of leaves at the top of 60’ whips, not a pretty sight. Once you have whacked them back, reward them with a shot of fertilizer and water them well. Then get ready to enjoy the show.

And what a show it will be. If your taste runs to the delicate, but profuse, early spring bloomers, Group A, then perhaps the perfect clematis for you is C. alpina ‘Frances Rivis’, which glows with pale blue nodding bell-shaped flowers.

The C. alpina species will also flourish in containers, so even those of you with limited space can still enjoy the beauty of a climbing clematis. Or maybe you pine for an evergreen vine to cover the ugly fence your neighbor had installed when you were away on vacation. Then choose C. armandii, a vigorous 25’ beauty from China, with fragrant white flowers or the popular cultivar C. armandii ‘Apple Blossom’, a clear pink evergreen variety.

For masses of flowers and vigorous vines (to 40’) no clematis can beat the montana species, with its profusion of white and pale pink blossoms, but to keep C. montana under control it should be cut back hard after flowering lest it get away from you.

If you want big, flashy flowers then focus your attention on the hybrids of Group B, but be prepared to wait for your first blooms until May or June. This category is dominated by popular white hybrids, an ideal choice to brighten up a dark corner or soften a sharp-edged wall. Two single flowered varieties are notable for their ease of cultivation and vigor. ‘Marie Boisselot’ bursts onto the spring stage with 8” blossoms and ‘Henryi’ with a lineage extending back to the 1870’s renown for its profusion of 6” blooms.

Two of the best double whites are the ‘Duchess of Edinburgh’,

a Victorian favorite, whose flowers assume a pale green tinge in shade, and ‘Arctic Queen’, introduced by the English in 1994. A newcomer to the clematis world, this precocious child is a real trouper, flowering all summer long. For some color in the shady garden, consider the popular, old-fashioned ‘Nelly Moser’ which debuts in late spring with pale mauve flowers sprayed with pink rays and then returns in late summer for an encore.

For those of you who have a very sunny spot, a fine choice would be one of the purple or red flowering clematis varieties, since their bright colors deepen in the sun. Consider, for instance, ‘The President’ an old favorite from 1876,

which is decked out with masses of royal purple blossoms throughout the summer, or the bushy ‘Barbara Jackman’ whose lavender flowers are sprayed with magenta rays. She’s a showstopper.

The large-flowered hybrids that begin blooming in late spring, June and July, comprise Group C, that category which flowers on current year’s growth. Since this group of climbers must be cut back hard in early spring before the new growth appears, they are ideally suited to grow through evergreen shrubs or among climbing roses or even shrub roses. Imagine the intense display of C. ‘Jackmanii’,

a mass of deep purple blooms intertwined with the delicate pink blossoms of the climbing rose ‘Cecile Brunner’.

C. ‘Jackmanii’ is one of the oldest and most widely grown of all the Group C varieties, possibly because it is one of the most frost hardy of the big blooming hybrids. Those of you who have been so fortunate as to visit Monet’s garden at Giverny in France will recognize the lovely 5” pale pink flowers of ‘Comtesse de Bouchard’ guaranteed to light up a shady spot.

Or if your taste runs to the lavender shades rather than the pinks, a long blooming old classic ‘Mrs. Cholmondeley’ also is suited for dappled light.

For a really sunny location, consider ‘Lady Betty Balfour’ a late bloomer that adds a shot of fuchsia to a fading summer garden. Another late summer performer that can add sparkle to a tired garden is ‘Ernest Markham’ a magenta red beauty noted for its vigor.

And no discussion of fall blooming clematis would be complete without mention of the delicate C. paniculata (or C. ternifolia), Sweet Autumn Clematis, a mass of tiny fragrant white blossoms, which occasionally can be spotted growing wild by the side of a rural road.

Since it can become unruly plant it where it can sprawl with abandon.

No matter what your gardening conditions or desires – double flowers, single flowers, early bloomers, late summer color, sun lovers, or shy shady ladies – there is at least one perfect clematis for your garden. Choose wisely, prune prudently, feed regularly and the queen of the climbers will repay you with a blizzard of flowers. Once those flowers have faded the show still goes on, the faded blooms replaced by delicate wispy seed pods which cling to the vine through the coldest months.

Plant Sources:

Clematis Specialty Nursery

Klehm’s Song Sparrow Nursery

Bluestone Perennials

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