Clematis

Clematis montana 'Rubens' © Isabelle van Groeningen

Clematis montana ‘Rubens’

The heat of the past days has caused our Clematis montana to scatter her palest pink petals like confetti all over the terrace. This year’s show lasted barely two weeks. Pity it is all over, even though we don’t actually see all that much of its glory anymore these days: This pleasure is mainly reserved for our neighbours that live on the second and third floor above us. In five years she’s shot up and has now arrived at the third-floor balcony. On the other side corner we have Mad Alf, properly known as Rosa ’Madame Alfred Carriere‘ with her large, strongly scented blousy flowers accompanied from my favourite Clematis viticella ’Etoile Violette‘.  This one flowers as the rose’s first flush is over, though in the case of Mad Alf she does not have much of a break in summer to regain her forces for a second flush, she rather ambles on with a gentle successive display of her wonderful blooms. With us she is rather weak, as she does not get quite enough sunshine.

Clematis Wilt

All of these climbers were planted before the wooden terrace boards were laid. This caused a minor disaster as the Clematis viticella was affected by Clematis Wilt within three months of planting her. This fungal disease starts at the tip of the shoots, causing them to wilt as if they are dry, and then rapidly progresses down to ground level where it stops. If caught early before the entire shoot is limp, it may be stopped by cutting the diseased shoot out. As it never affects the plant below ground level, Clematis should always be planted three or four centimetres deeper than normal, so some buds can emerge from below soil level, which is what mine did. I had written it off, assuming it would have died after failing so shortly after planting, but next spring it re-emerged as if nothing happened, and has done so ever since.

Pruning Clematis

Clematis tangutica © Isabelle van Groeningen

Clematis tangutica

The spring-flowering ones like C. montana, alpina and macropetala all flower on old wood, the buds having been prepared in autumn. Therefore, they should not be pruned before flowering, making them unsuitable for a winter or spring prune. If at all, they should be cut back lightly after flowering. (If a drastic prune is required, then this should be done at the start of the season, do not wait for the flowers.) The same applies for species like the divinely perfumed very early but not so hardy C. armandii. Clematis tangutica with its thick, fleshy yellow petals is also one to treat lightly. The charm of leaving these species untouched is the second show they put on when their seed heads develop into silky soft silver wigs.

The summer flowering hybrids that flower from June upwards produce buds on new growth and can therefore be cut back harder during the winter months. I recommend doing this quite early, as their new shoots appear virtually overnight with great vigour with the first warmth in early spring.

Where to plant Clematis

In their wild habitat, most Clematis grow in amongst trees, with their feet nice and cool. They will shoot up into the upper parts of the canopy, and then spread themselves out over the tree leaves looking for the sunlight to flower. This explains why it is so important to keep the base of the plant cool. It is possible to buy specially made terracotta tiles for this purpose, but better still is to put another plant on the south side. This will provide ample, cool shade which the plant will prefer. Plant the vigorous species there where they have sufficient space to climb up. C. montana cultivars like ‘Rubens’ or ‘Fragrant Spring’ will reach high up into trees or cover several storeys of an east or west façade a building.

For an arch, pergola or climbing support in a border I quite like the not so vigorous larger summer-flowered flowered hybrids like ‘Mme Lecoultre’, ‘Hagley Hybrid’ or ‘Tudor’.

Clematis in roses

clematis 'Niobe' © Isabelle van Groeningen

clematis ‘Niobe’

Climbing roses always get a clematis as close companion from me. For this I prefer using the somewhat smaller flowered mostly viticella hybrids. C. viticella ‘Alba Luxurians’ with its green-tipped white petals is a delight in darker coloured roses. The red `’Niobe’ is interesting with softer pinks, whilst the dark ‘Etoile Violette’ manages to contrast well with reds and yellows. None of these overwhelm the roses and can be cut back and pulled out from among the growth before it is pruned back. By the time the rose has finished it’s first flush of flowers, the clematis will have started flowering, and most will continue to do so until the rose has caught its breath and started again in August. This makes double use of the space, which is very valuable in smaller gardens.

Clematis viticella 'Alba Luxurians' © Isabelle van Groeningen

Clematis viticella ‘Alba Luxurians’

Climbing support

Clematis prefer to hook themselves onto thinner wire or twigs. A thick cane or piece of wood they cannot get their arm around so easily. Ideal is galvanised wire mesh, its matt, greyish colour blending in with most stone- or brickwork and timber.

Climbing wire in Sissinghurst © Isabelle van Groeningen

Climbing wire in Sissinghurst

Clematis in containers

Raymond Evison, the famous Guernsey-based Clematis breeder has been breeding compact forms for many years. I used to wonder what the point of them was, until I moved to Berlin and started experimenting with container planting. His range of “Boulevard” cultivars like ‘Cezanne’ are particularly suited to growing in a container and will flower from spring until early autumn. Important is to give them a generous pot, and make sure its feet are kept shaded.

Make use of these charming, versatile colours providers. They deserve your attention!