With such a small footprint yet huge flowering potential, clematis are a must for any garden, no matter what its size. Anne Swithinbank explains how to grow clematis
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Clematis mingle well with existing climbers and wall shrubs, taking up little extra space. They can deliver flowers every month of the year and are largely self-clinging, grabbing on to their supports with twining leaf stalks.
The best times to plant clematis are early autumn and now, in spring, when the soil is still moist but warming up.
April and May belong to Clematis alpina, C. macropetala and their cultivars. Undemanding and very hardy, these dainty clematis with pretty nodding flowers perform well in average soils and any aspect, so long as their roots are shaded from strong winds and sun.
They are soon joined by romping C. montana, another easy-going type with so many blooms you can hardly fit a pin between them. Fragrant pale-pink ‘Mayleen’ is a particularly good choice, and if any of these spring clematis need pruning, ensure you do so immediately after they’ve flowered.
During May and June, large-flowered hybrids such as ‘Nelly Moser’ and ‘Niobe’ open their massive blooms. These are more particular and, if left to their own devices, will pine and dwindle. In late winter, trim stems above their topmost pairs of fat buds and again after the first flush of flowers.
‘Niobe’ boasts impressive giant blooms that unfurl in May and JuneAs summer progresses, late flowering, sun-loving Viticella hybrids such as ‘Etoile Violette’ open from June to September. These are pruned hard in late winter, back to 12in (30cm) beyond strong buds.
For late summer and autumn, C. texensis cultivars with blooms that resemble inverted tulips, begin to join in. These tend to die right back during winter and push from just below ground each spring. All these summer flowerers need a high-potash rose fertiliser or similar in springtime, followed by a generous mulch of well-rotted compost and a couple of liquid feeds.
The ‘lemon-peel’ blooms of C. orientalis and C. tangutica turn into wispy seed heads, overlapping with the muted but welcome midwinter display from evergreen C. cirrhosa cultivars.
These need lots of sun and a sheltered spot. The New Year is heralded by C. ‘Winter Beauty’ and then vanilla-scented C. armandii – both evergreens in need of a sheltered spot. Ensure any necessary pruning is meted out promptly after flowering.
When tackling overgrown borders containing clematis, find and wrap their bases in easily visible horticultural fleece. Without this, the brown, dead-looking lower stems are all too easy to rip up along with weeds.
Like other C.alpina varieties, this is good at looking after itself. Expect nodding blue flowers on plants reaching 2.5m (8ft). Ensure roots are shaded and prune after flowering.
‘Comtesse de Bouchard’
A tough, easy, pink clematis, which is happier in shadier positions. Reaches 6-8ft (1.8-2.5m), and blooms from June to September. Prune hard in late winter, or more lightly for earlier flowers.
A distinctive Viticella type with wine-red flowers from June to September on plants to 12ft (3.7m). Prune in late winter.
C. x triternata ‘Rubromarginata’
Creates a mass of tiny stars with maroon-edged petals and an almond scent. Tolerates dry shade and grows to 10ft (3m).
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- Plant into well-conditioned, well-drained soil.
- Position the plants somewhere they’ll have cool roots but sun further up, though many are shade tolerant.
- Plant large-flowered summer-blooming clematis so their stem bases are buried 2-3in (5-8cm) below soil level (see image above). Plant the rest normally.
- Prune spindly newly planted clematis to 12in (30cm) above soil level to encourage multiple stems.
- Water during droughts while establishing.