Most of us are familiar with the showy, large-flowered clematis that begin their parade this month.
Clematis is cool, says Kerry Carman.
It is easy to enjoy their gentle twining ways and fountains of bloom that so enhance our trellises, archways, terraces and courtyards, chatting amiably with our climbing roses, and providing evergreen shrubs and small trees with another season of colour. In short, generally gracing our gardens with their vibrant or pastel petals.
Some of my favourites over the years have been in this large-flowered group: ‘Nelly Moser’ and her children ‘Bees’ Jubilee’ and ‘Barbara Jackman’, velvety purple ‘Elsa Späth’, glowing ‘Fireworks’, claret ‘Niobe’ and tender pastels ‘Louise Rowe‘, ‘Hagley Hybrid’ and ‘Pink Fantasy’ (a compact grower good for a container). The long-flowering double ‘Belle of Woking’ in tender shades of silvery mauve and apple green peeps in my window all summer long.
But it is the more unusual species, cultivars and fragrant forms that extend the season and bring so much delight throughout the year, particularly the scented summer Clematis flammula and autumn’s Clematis terniflora.
The herbaceous forms Clematis integrifolia, Clematis heracleifolia and Clematis x jouiniana with their more colourful hybrids ‘Rooguchi’ and ‘Arabella’ form another long flowering group.
What all clematis have in common is the need for their roots to be cherished.
They like cool, shaded moist soil, preferably rich in leaf mould, where they can climb up to have their heads in the sun. One way to achieve this is to place a large flat stone or paver over the root area after planting.
All are rich feeders, the quantity of blooms directly relating to the amount of nourishment supplied. One specialist grower advises the application of blood and bone in early autumn, horse manure, homemade compost or Nitrophoska Blue in spring, then chicken or sheep pellets every following three weeks.
I give mine occasional doses of liquid seaweed if I think they need it.
The main thing is not to let them dry out at the roots in our long hot summers.
An aid to this is to sink a length of pipe vertically into the ground at planting time. Leave a little above ground, into which you can pour water
to reach the root area more effectively.
Following the early spring blooming of our native species come the many lovely hybrids of Clematis alpina, Clematis armandii, Clematis macropetala and
Clematis montana groups. But Clematis armandii is no plant for the small garden as, once established, it will swiftly romp away creating overwhelming cascades of blooms to cover the tops of trees for metres in every direction. Its hybrid ‘Apple Blossom’ is more restrained. My plant now forms a shining mantle of close-packed pale pink blossoms over the top of an old lemonwood hedge, its luminous flowers strongly fragrant of vanilla in the moonlight.
If you want a blissful bower to retreat to on hot midsummer days, try the intensely fragrant Clematis flammula (aka virgin’s bower), followed by the similar
Clematis terniflora for autumn. Team these with a long-flowering climbing rose such as ‘Madame Alfred Carrière’, who won’t mind the shade cast by the clematis, which will produce gusts of fragrance through the summer nights.
Perhaps it is the herbaceous, non-climbing clematis that are so useful in garden borders. Clematis recta strews its surroundings with a cloud of white stars as does the purple-foliaged form which extends the season with colour. Plant this one in the sun as dark-leaved plants struggle to photosynthesise in shade.
Clematis x jouiniana, Clematis
heracleifolia, Clematis integrifolia and their offspring are all non-climbing but will happily scramble along at ground level to provide groundcover and suppress weeds. Most have fragrant, ice-blue flowers.
Two favourite cultivars in this group are violet ‘Arabella’ which neatly covers the bare-legged lower regions of my yellow ‘Graham Thomas’ rose while nearby, Japanese-raised ‘Rooguchi’ thickly covers a metal tripod with myriads of purple and white lantern-shaped blooms with recurved petal tips.
Both ‘Arabella’ and ‘Rooguchi’ are extremely long flowering. I cut them back to the ground in winter though they will flower on both old and new wood.
As a general guide, most clematis do well if pruned directly after flowering – except for those that flower in late autumn and winter, blooming only on the current season’s growth.
Scented Clematis terniflora.
‘Belle of Woking’.