Adrienne Wild extols the virtues of clematis, whose enormous variety make it ideal for any role in the garden, from covering pergolas and walls to making a bold statement on the patio
Clematis blooms come in a variety of shapes, from tiny bells and lanterns to enormous glittering stars. Flowers can be singles or petal-packed doubles and range in colour from white to yellow through shades of pink, red and purple – plus there are some striking colour combos to choose from.
Some varieties also have an unusual fountain of short, pointed, quill-like petals above an outer layer of flat petal-like sepals, or, like ‘Crystal Fountain’, come with a splendid ruff of stamens in the centre, which makes them a fascinating group of plants that many gardeners obsessively collect.
You don’t need much imagination to get the best out of clematis as the varieties available give unlimited freedom to combine them with other plants, clothe walls, pretty-up pots and smother bare ground to decorate the garden any month of the year.
Summer is when the majority are at their peak and most require at least five to six hours of sun per day to thrive, although delicately coloured blooms tend to bleach in harsh sunlight so are best planted in light shade. They all enjoy moist, well-drained, slightly acidic soil and need a cool root run to thrive, so it’s advisable to mulch around the roots or shield them with low-growing plants.
House walls are the obvious place to display clematis and a reliable partnership for sunny or partially-shaded walls is the purple ‘Warsaw Nike’ threaded through the hand-sized rose-pink flowers of ‘Comtesse de Bouchaud’. Both plants bloom vigorously and continuously from June through September.
On a shady aspect go for ‘Niobe’, that will reliably produce dark ruby blooms from June through September, and ‘Nelly Moser’, which in early summer shines with pale blooms up to 20cm in diameter that have distinctive gleaming lilac bars on each petal.
When planting against the house, be aware that the roof overhang may cause a ‘rain shadow’, stopping rainwater reaching the plant. So plant the root ball of any climber at least 60cm away from the base of the wall.
And with clematis, always bury the root ball slightly deeper than it was growing in the pot and with the first set of true leaves lying just under the soil surface, so if the plant is ever struck down by the dreaded clematis wilt, it should recover.
Clematis wilt causes plants to collapse without warning, so it won’t go unnoticed as plants will turn brown and die back in just a few days. Hoe or slug damage are often thought to be entry points for the fungus which causes the problem, so as a precaution put a plastic collar around the base of the plant – you can easily make one out of a split plastic pot.
As you’d expect from a climber, clematis is perfect for training on to arches. For easy maintenance, choose varieties that don’t grow much taller than 2-3m, such as ‘The President’, ‘Vyvyan Pennell’ and ‘Arctic Queen’.
Plant one on either side of the arch and allow them to crawl over each other to cover the frame. C. viticella ‘Polish Spirit’ will tolerate shade as will the ever-popular ‘Nelly Moser’.
Pergolas are great for creating floral corridors within the garden as well as shady spots to rest. They look best when clothed with a variety of climbers, including summer annuals like morning glory and the Chilean glory vine that will give a quick cover-up.
Clematis and roses will make a permanent summer feature and, again, you won’t go far wrong with Clematis ‘Comtesse de Bouchaud’, alongside the pink roses ‘James Galway’ or ‘Gertrude Jekyll’. Early summer-flowering Clematis ‘Lasurstern’ is another good choice and the purple blooms contrast well with pinkish-mauve and yellow-flowered roses.
The velvety dark purple, flowers of ‘Jackmanii Superba’, look wonderful against soft pink blush blooms.
Late-flowering clematis such as ‘Jackmanii’ are not only useful for training into roses and other shrubs and even across ground cover, but are a good choice for north-facing beds where you can train it up poles and obelisks to create a focal point. They can also be grown successfully over a wigwam in a large container, as can ‘Fragrant Oberon’, a compact climber, which has lemon and white flowers with a hint of green set against dark evergreen foliage.
Given the right growing conditions, clematis will thrive, but it’s pruning that is the key to success. It encourages flowering but you need to know that some do best when pruned right after blooming while others prefer an early spring trim.
Check the plant label for information on the approach that’s best for your clematis.