Climbing plants are a great way to add colour and interest to your garden. And for sheer range and variety, clematis stands head and shoulders above the rest, says Adam Appleyard.
Climbing plants – and clematis in particular – can quickly transform a so-so garden into a magical one.
Do you have trees or shrubs that look gorgeous in spring or autumn but dull as ditchwater during the rest of the year? Then plant a clematis to grow up through them! Is your plot bordered by a forbidding wall or featureless fence? Slap on a trellis and let clematis pep it up with bright splashes of colour. Is your garden short of structure and height? Install an obelisk, screen or pergola and – you’ve guessed it – train a clematis or two to scramble over it!
SOMETHING FOR EVERYONE
There are hundreds of different varieties of clematis, and they come in a seemingly limitless palette of colours. These include snowy whites, primrose yellows, lime greens, cool blues, punchy purples, pretty pinks and fiery reds.
The shapes of clematis flowers are almost as varied as their colours, and range from the shy, delicate, nodding heads of C. alpina and C. koreana to the bold, saucer-sized blooms of mid-season hybrids like ‘Fireworks’ or ‘Diamantina’. And although most clematis aren’t notable for their scent, there are nonetheless varieties such as C. armandii ‘Appleblossom’ or C. montana ‘Vera’ that will perfume your garden with wafts of subtle, honeyed fragrance.
Thinking in purely practical terms rather than aesthetic ones, if you do your research you’ll be able to find a clematis to thrive in pretty much every garden slot you might want to fill. For sheltered locations in full sun, for example, florida types are ideal. Alpinas and macropetalas, on the other hand, will happily withstand windy, exposed locations and arctic temperatures.
If you struggle with overly dry soil, dig in a spadeful or two of compost and plant C. flammula or C. triternata. And if you want to cheer up a dark corner there are several clematis that will happily grow in shaded spots – even north-facing walls aren’t necessarily out-of-bounds. These shade tolerant clematis include the striking electric blue C. ‘Fujimusume’ and the silky white C. ‘John Huxtable’.
There’s only one type of environment that all clematis hate, and that’s waterlogged soil. But even if your soil is damp or clayey, you can still grow clematis very successfully in containers.
Choose generously proportioned pots – 50cm wide by 50cm deep is a minimum – and fill the bottom few centimetres with a layer of gravel. It’s also a good idea to raise your pots above ground level with ceramic ‘pot feet’ to prevent them soaking up standing water or snow melt during winter. Once your clematis is planted, cover the surface of the soil with bark or stone chippings to keep the roots cool.
Whether you’re growing them in containers or planting them directly into the soil, Group 2 clematis (see text box) should be ideally be positioned with the tops of their root balls 8–10cm beneath soil level, and all types of clematis should be cut back to 20–30cm above ground level the first spring after planting. This will encourage the development of multiple stems, helping your clematis to develop a satisfyingly full, bushy shape rather than issuing from a single straggly stem.
PERFECT PRUNING FOR BOUNTIFUL BLOOMS
Many gardeners get in a tizzy about pruning clematis, but once you know the rules it’s easy enough. Clematis can be divided into three groups according to their flowering pattern, and for two of these three groups, pruning is simplicity itself.
GROUP 1 EARLY-FLOWERING CLEMATIS
This group includes C. alpina, C. armandii, C. koreana, C. macropetala and C. montana, and its members flower from January through to early May on shoots the plants produced the previous summer. And here’s the good news: you don’t need to prune Group 1 clematis at all. Well, not unless you need to get rid of damaged stems, or prevent vigorous species like C. montana from spreading too far – in which case do it as soon as the plant has flowered. If have a montana or other hyperactive clematis that has become ugly and tangled through years of neglect, simply cut it back to a few centimetres above ground level and give it a generous feed. It will promptly grow back, and in a much more manageable form.
GROUP 2 MID-SEASON CLEMATIS
These are large-flowered hybrids that bloom from May to June, sometimes with a second flush of flowers in late summer. They include big blowsy stunners like ‘Nelly Moser’, ‘Marie Boisselot’ and ‘Rebecca’. Prune them immediately after the first flush of flowers has finished, cutting stems back by approximately one third, then feed with high-potash fertiliser. This will encourage a second flowering from August onwards. Prune once again in February or March, lopping off weak or damaged sections and shortening stems by a further one third. If this routine sounds too much like hard work, prune as per Group 3, below, once every three or four years – just don’t count on getting more than one flowering per year.
GROUP 3 LATE-FLOWERING CLEMATIS
These are species with medium-sized blooms that flower from July onwards, and they include C. viticella, C. texensis and C. tangutica. Left to their own devices they will quickly turn into long, leggy plants that flower as high above your head as they can contrive to reach. To keep them at a height where they can be more easily appreciated is easy enough. Simply sharpen your secateurs in February or March and cut stems back to 20–30cm above ground level, snipping directly above a strong pair of leaf buds.