I have often thought there are few sights in gardening more depressing than a clematis in winter. The ragged remains of what was once a glorious spectacle now hang as miserably as Miss Havisham’s cobwebs from trellis, fence, wall and tree. None of this, however, is intended to deter you from growing them or even planting extra – but at least the coming weeks offer the opportunity to make the things look a bit tidier.
There are probably more ideas about clematis pruning than there are gardeners, largely because our familiar garden varieties are derived from such a wide range of wild species, all with different growing patterns and flowering times. However, I have my own truly simple and easy to remember rule that may offend clematis purists, but which has worked admirably for me down the years. And February is when to put it into practice.
I prune all my clematis this month and my guiding principle is: the later in the year that each kind flowers, the harder (or more severely) it should be pruned. Hence, the spring-flowering types such as the exquisite violet-blue-flowered “Frances Rivis”, derived from the southern European Clematis alpina, are lightly cut back by about 30cm; all the summer-flowering kinds, including the giant-flowered hybrids, are cut back by about half; and the autumn- flowering types – including the yellow- or orange-flowered varieties derived from the various oriental species – are cut back to about one metre above soil level. The one oddity is the extremely vigorous and well known spring-flowering Clematis montana varieties (among which, to my mind, the best, and almost only scented type is “Elizabeth”). These can be cut back as hard as you like to keep them within bounds.
I am often asked to name my favourite plant varieties, but as there are over two and a half thousand clematis on offer, the challenge is tougher than usual. That said, there are some that my garden would be the poorer without, and I shall commend three of them. First: the rose-red, summer-flowering “Mme Julia Correvon”, with cream-yellow stamens and slightly nodding blooms; second, the early-summer-flowering “Marie Boisselot”, with very large blooms, and probably the best white-flowered clematis ever raised; and third, the so-called golden clematis, Clematis tangutica, with masses of lantern-like nodding yellow flowers in late summer and on into autumn.
Mention of the really vigorous clematis, such as the orange-yellow-flowered autumn-blooming species and those derived from Clematis montana, highlights a further point. Much like most kinds of honeysuckle, they are not really at home on trellises or house walls. They are so energetic they soon become an unruly, tangled, rope-like mass. Put them where they grow naturally: up and over old trees – ancient apple trees are ideal – and if your garden is too small or does not offer such habitats, my advice is to limit yourself to other, less vigorous kinds.
It is often suggested that clematis make wonderful companions for climbing roses, especially older rose varieties. Choose types of clematis and rose that flower at the same time in early summer and you can create some memorable complementary colour combinations. But be warned: a miserable winter clematis growing through a climbing rose is still a miserable winter clematis – and immeasurably more difficult to prune when you have to unravel it from a seriously thorny rose.
This article appears in the 06 Feb 2019 issue of the New Statesman, Broken Europe