Over 70 species and cultivars of clematis currently (2016) possess the Royal Horticultural Society's Award of Garden Merit, reflecting this plant's continued popularity in gardens in the United Kingdom. Clematis is a genus of woody based perennials, mostly climbers with a twining habit, though some are grown as groundcover or as herbaceous plants. They can be evergreen or deciduous. They bear flowers in all shades except black, pure blue, pure red and orange. The flowers are often large and showy. They can be single or double, fragrant or unscented, compact or vigorous, in a wide range of shapes and sizes. The flowering period varies from early spring to late summer. Many spring-flowering cultivars produce a second flush of blooms after the main display has finished, and many have attractive silky seed-heads prolonging the period of interest. Clematis can be grown against walls, fences, over pergolas and obelisks, or through other shrubs and trees.

Groups

Cultivars are placed in the following groups:- A; Atragene group; medium-sized climbers with nodding, bellshaped flowers early in the season Ad; Atragene double-flowered; medium-sized climbers with nodding, bell-shaped double blooms flowering in spring on previous year's growth E; Early large flowered group; medium-sized climbers with large star-shaped flowers on previous season's growth, in spring and early summer, often with a second flush of blooms later in the season Forsteri group; dwarf or spreading evergreen shrubs or climbers, with deeply cut leaves and small white or cream flowers H; Heracleifolia group; subshrubs with long, scrambling stems and abundant small flowers on the current year's growth, in summer and autumn I; Integrifolia group; small subshrubs with herbaceous growth, flowers in summer and autumn L; Late large-flowered group; medium-sized climbers flowering in summer and early autumn on current year's growth, with large flowers M; Montana group; vigorous climbers flowering early in the season Md; Montana double-flowered group; vigorous climbers flowering in late spring and early summer T; Tangutica group; large climbers with small bell-shaped flowers, usually in shades of yellow or white, late in the season, often followed by silky seed heads Tx; Texensis group; climbers with bell- or tulip-shaped flowers in summer and autumn, on the current year's growth V; Viticella group; pinnate leaves, nodding half-open flowers on current year's growth, in summer Va; Vitalba group; substantial climbers with profuse, small, erect flowers on current year's growth, in summer and autumn; also used for groundcover

Name Species Group Colour Dia. H W Image Abundance V red (wine) 7.5 4.01.0 Alionushka I pink (rose) 5.0 1.5 0.5 'Evithree' E purple/cerise 15.0 4.0 0.5 Apple Blossom Ar white 6.5 8.0 2.5 Arabella I blue (mauve) 9.0 2.5 1.0 'Evitwo' E white 15.0 4.0 1.0 Ballet Skirt A/d pink 10.0 2.5 1.0 Bill MacKenzie T yellow 7.0 8.0 4.0 Blekitny Aniol L blue (pale) 10.0 2.5 1.0 Broughton Star MD pink (deep) 6.0 8.0 5.4 Cassandra C. heracleifolia blue 1.0 0.5 C. montana var. grandiflora M white 7.0 12.0 4.0 C. rehderiana yellow (pale) 2.5 8.0 2.5 C. × durandii blue (indigo) 10.0 2.5 1.0 Comtesse de Bouchaud L pink (rose) 15.0 2.5 1.0 Constance A pink (deep) 5.0 2.5 1.5 Daniel Deronda E blue (violet) 20.0 2.5 1.0 Elizabeth M pink (pale) 6.0 12.0 4.0 Ernest Markham L red (crimson) 15.0 4.0 1.0 Étoile violette V purple 10.0 4.0 1.5 Foxy A pink (pale) 5.0 2.5 1.5 Frances Rivis A blue (violet) / cream 5.0 2.5 1.5 Frankie A blue (violet) / cream 5.0 2.5 1.5 Freckles C. cirrhosa var. purpurascens yellow (pale)/maroon 5.0 4.0 1.0 Freda M pink (deep) 5.0 8.0 4.0 Fujimusume E blue (pale) 20.0 1.5 1.0 Gillian Blades L white 15.0 2.5 1.0 Gipsy Queen L purple 14.0 4.0 1.0 'Kugotia' T yellow 4.0 8.0 8.0 Hågelby Pink' Vt pink (pale) 4.0 1.0 'Zohapbi' L purple 10.0 3.0 1.5 Helsingborg A purple 5.0 2.5 1.5 Huldine L white 10.0 4.0 2.5 Jackmanii L purple 10.0 4.0 1.0 Jacqueline du Pré L pink (rose) 6.3 2.5 1.5 Joe C. × cartmanii F white 4.0 1.5 0.5 Ken Donson E blue (deep) 3.0 0.5 Kermesina V red (crimson) 6.0 4.0 1.5 Lagoon C. macropetala A blue (violet) 7.5 2.5 1.5 Lambton Park T yellow 7.0 8.0 4.0 Lasurstern E blue (lavender) 7.5 2.5 1.0 Madame Julia Correvon V red (claret) 12.5 4.0 1.5 Marie Boisselot E white 20.0 4.0 1.0 Markham's Pink AD pink 5.0 4.0 1.5 Mayleen M pink (pale) 7.0 12.0 2.5 Minuet V white/pink 5.0 4.0 1.0 Mrs Cholmondeley E blue (lavender) 20.0 2.5 1.0 Mrs George Jackman E white 18.0 2.5 1.0 Nelly Moser E pink 20.0 2.5 1.0 Niobe E red (ruby) 15.0 2.5 1.0 Pamela Jackman C. alpina A blue (deep) 7.0 2.5 1.5 Pangbourne Pink I pink (mauve) 5.0 1.0 0.5 Paul Farges Va white 4.5 8.0 2.5 Pauline Ad blue 2.5 1.5 'Evisix' I blue (violet) 9.0 1.0 1.0 Pink Flamingo A pink (pale) 4.0 2.5 1.5 Poldice V violet/white 4.0 1.5 Polish Spirit L purple 9.0 4.0 1.0 Praecox H blue (pale) 2.0 4.0 2.5 Prince Charles L blue (violet) 10.0 2.5 1.0 Princess Diana Tx red (magenta) 10.0 4.0 1.0 Purpurea Plena Elegans VD purple/pink 5.0 2.5 1.0 Remembrance LL pink (deep) 12.0 2.5 1.5 Richard Pennell E purple 20.0 2.5 1.0 Roko-Kolla LL white 15.0 2.5 1.0 Sunset E red (magenta) 12.0 2.5 1.0 Tetrarose C. montana var. rubens M pink (mauve) 7.5 8.0 2.5 The President E blue 18.0 2.5 1.0 Venosa Violacea V purple/white 10.0 2.5 1.0 Walenburg V purple/white 3.0 1.0 Warszawska Nike EL purple 18.0 2.5 1.0 Wesselton C. macropetala E blue (pale) 2.5 1.5 White Columbine A white 5.0 2.5 1.5 Will Goodwin EL pale violet 15.0 2.5 1.0 Wisley Cream C. cirrhosa yellow (pale) 8.0 4.0 1.0 'Evipo001' Vt blue/red 13.0 4.0 1.5

References