When most of us think about clematis (accent on first, not second syllable), we seldom get beyond the large-flowered climbers that adorn mailboxes, lampposts, and other gawky supports. They may look gorgeous in catalogs and exhibits at the Chelsea Flower Show, but in my own experience at least, the large-flowered vines have proven to be problematic at best, as the foliage and roots succumb quickly to clematis wilt, a fungal disease.
Despair not. There are a good many other, unfamiliar, types that flower throughout the summer, two or more months. Really. Some integrate seamlessly in a perennials garden, while others can cover a wall or trellis, disport gracefully through a tree or shrub, or even act as a large groundcover in sunny places. What’s more, they have lovely smaller flowers that are not prone to disease and require little in the way of maintenance.
Why they are not better known is a mystery. They are nothing if not versatile.
Clematis integrifolia is one of the non-vining herbaceous clematis. Mine is the cultivar Caerulea that has had pride of place at the front of my sunny perennials garden. Its deep-blue flowers, like many of the small-flowered varieties, look like court jester caps or bells with reflexed bottoms. It blooms from June into August on a low (a little taller than two feet) shrubby-like bush that we support with a bamboo teepee. Purchased more than 20 years ago from Heronswood Nursery, it only requires cutting back late in the year and reinstalling the teepee in spring. It would be a great addition to any perennials garden and is reported to be available from Monrovia.
Just last year I discovered an integrifolia hybrid, C. x durandii, that is a keeper. Its large deep-purple flowers with showy cream stamens have been in bloom since June and show no sign of halting. It is another non-vining herbaceous type. In my garden it threads its way through the white and green evergreen foliage of the cherry laurel, Prunus laurocerasus Castlewellan. Dan Hinkley grew it as a mid-border plant with black-leaved cimicifuga, a “delicious combination,” he reported. Graham Stuart Thomas thought it superb with yellow crocosmias.
A few years ago a groundcover with masses of clusters of milky white and pale blue flowers caught my attention at the Battery Park garden designed by Piet Oudolf in lower Manhattan. It was not showy in the conventional sense, but densely covered a large area in the sun. The head gardener said it flowers for several months and is available from only one nursery in the United States, Brushwood Nursery in Athens, Ga.
It is C. x jouiniana Praecox, another of the non-clinging herbaceous clematis. It has pulled together disparate young perennials, trees, and shrubs in a newly planted sunny area in my garden. It scrambles through a grouping of hostas, where the clematis flowers intensify the blue tones in the hosta leaves; links the bright yellow in some hostas to nearby clumps of yellow daylilies, and covers a young rhododendron with flowers, which when its own flowering season is over, doesn’t have much to offer. So far the clematis covers about 50 square feet, but in the future may grow much larger. That won’t be a problem: When it’s time to cut back the perennials, it, too, will be cut back to the ground.
Clematis recta Purpurea is one of the most well-known of the herbaceous clematis, but for me is one of its disappointments. Some have washed out purple-green leaves rather than the deep black that is publicized. Mine is deep purple, but during the season and after flowering, I forget to cut the whole thing down to encourage a second flush of dark leaves and flowers and the color fades. Purple-leaved cimicifugas would be a better bet.
The viticella hybrids are easy, small-flowered clinging vines that should be in every garden. Betty Corning is unmistakable. It has silvery-lavender, court jester-like flowers on long pedicels on an open vine. It grows at least eight feet into an open holly in my garden where the caps dangle in the breeze. Jim Jeffrey grew several on trellises near the corners of his house, but his most successful climbs up a Hinoki cypress, where the dark green of the conifer showcases the flowers. Betty Corning accepts a fair amount of shade, much more than others, without sacrificing its flowers.
Clematis viticella Etoile Violet has proven to be vigorous here, covering a large south-facing wall at the back of my perennials bed. It has good-size deep-purple flowers that bloom profusely in June and July, and intermittently afterward. It is such an easy and beautiful flowering machine that we’ve been offering it at the garden club plant sale for the last couple of years. A friend grows Polish Spirit, which seems similar in flower and robustness.
Clematis Roguchi and Venosa Violacea are two other viticella hybrids that I grow, but in the wrong places. C. Roguchi, from Japan, has dark purple bells and is quite popular, easy to find in mail-order nurseries. My Roguchi was moved to a sunny location where I hope it won’t take too long to establish to climb a dwarf yellow-needled Japanese white pine. The two-toned flowers of Venosa Violacea are stars, with broad edges of deep purple and pale centers. It is gorgeous and is said to be easy, long blooming, and good to run up a spring-blooming tree. Gorgeous it is, but mine apparently receives too much shade under the Prunus mume. This year I didn’t see any flowers. Perhaps in another location. . . .
Clematis Duchess of Albany has two-tone pink bell-shaped flowers that bloom over a long period in summer. It grows and grows and grows. We have it on a trellis against the rear wall of the garage, flanking a pear espalier; when it reaches the top of the wall, we chop it, then tie in the side shoots and it erupts into a fountain of flowers. Duchess of Albany is a texensis hybrid and requires a little more effort than the viticellas. I’ve found that if the new shoots in spring are not reduced to three or four (and this is as difficult for me as culling the deer herd is for some), it will have a lot of foliage and few flowers. Steel yourself for the deed and you will be rewarded.
All these summer-blooming clematis flower on new growth and are cut down to the ground (or just above the nodes where the first buds break on woody stems) when they go dormant. I’m not sure you need to add lime to these clematis, but we do every spring, along with a small trowel of basic fertilizer.
I have had good experiences with Dan Long, owner of Brushwood Nursery (gardenvines.com), which specializes in vines of all sorts.
These “other” clematis are easy and beautiful. Try them; this is the perfect time to order for autumn delivery and you can enjoy them next year.