Growing Clematis
By Howard Drury
Introduction
Clematis are members of the same family as the Buttercup and Anemone. Their attractions vary in their sometimes highly coloured sepals, which surround the central boss of anthers. Most are climbing plants, scrambling upwards by twisting their stalks around any suitable object. This makes them highly suited in the garden, growing through shrubs which flower for only a brief time, so prolonging the period of interest. Different species are found all around the globe, from Europe to Australasia and so, cultural requirements differ widely. The deciduous species and hybrids are reasonably hardy, whilst evergreen species need a warm wall or conservatory in which to grow.
Flowering season
Varieties and species of Clematis can be selected to give an extremely long flowering season. Clematis cirrhosa, if planted in a very sheltered position will flower in mid-winter and early spring, followed in April by Clematis armandii, alpina macropetela with the montana following in May. Later in the same month the large flowered hybrids excel. The final group which includes jackmanii and viticella continue flowering from June until the first frost of autumn.
Cultural requirements
Position it is not always appreciated how many different positions are suitable for growing Clematis. Many varieties will grow and flower quite freely in a shady situation and the lighter coloured forms such as 'Nelly Moser' will fade if given too much sun. Clematis associate well with roses, whether on walls or as free growing bushes. In mixed borders and shrubberies, they should be included to ramble up and through the more vigorous shrubs. They also look very effective when used to trail through low growing plants such as Heathers and Helianthemum. For hiding unsightly structures and growing up tree stumps, the vigorous species and small flowered hybrids are especially well suited. Many of them will make 20ft of growth in a single season.
Planting
Clematis are sold in pots and so may be planted at any time of the year, provided that it is neither too cold nor dry. Once planted they can be moved, if necessary, and this can be done successfully before growth begins in March. As with any plant, the best results are obtained by preparing the ground for planting. A hole should be dug 18" deep and into this place some well rotted manure or compost, cover lightly with soil and removing the pot, gently tease some roots away from the soil ball. The plant should then be placed in position, ensuring that two or three buds are below ground level, and the soil, which has been lightly mixed with bonemeal, replaced and firmed, followed by water, water and yet more water. Clematis have huge appetites for food and water, a weekly dose of tomato fertilizer during the growing season will not only increase the intensity of flower but also increase winter hardiness. Sheltering the base, either by a mulch of compost or by growing a low ground covering plant beneath, will also help to conserve moisture. When planting against a wall or trees the requirement for water must be taken into account and the planting carried away from the base of the wall or tree, areas which are generally dry.
Deep planting protects the plant from permanent damage from the hoe or strimmer and will allow further shoots to emerge should Clematis wilt occur. When growing in a tub or container (min. diameter. 50 cm or 20"), watering will be required every day during dry weather. Good drainage and a suitable compost, such as John Innes No. 3, is essential to obtain the best results. Most suitable types to choose are the alpinas, macropetala's and the early flowering hybrids. Hard pruning in the first two years will achieve a well-balanced plant followed by more judicious pruning later, as the plant grows.
Pruning
The time and type of pruning required depends upon the Clematis being grown. Full Details are given for each group later in this Fact Sheet.
Propagation
Clematis may be grown from seed, cuttings or by layering depending on the variety. The easiest method, particularly for amateurs, is layering, where there is no need for a greenhouse or heat. You require a well-developed plant with lots of vines (shoots) growing from the base. The varieties which are cut back almost to the ground each February will produce stems for layering by August. Fill a 5" pot with compost and sink in the ground. Make a slanting cut 1 to 2" behind the node on the underside. Dust with hormone rooting powder. Peg stems down into pot, cover with soil and a stone. Leave for 12 months before severing from parent plant. Do not allow pot to dry out during periods of drought.
Sow seeds of early flowering species in late summer/early autumn. The seeds should be covered lightly with sand and/or vermiculite and placed in a cold frame or even outside. By next summer, they should be ready for pricking out into larger pots. Late flowering species can be sown in March as above, but may take until the following spring to germinate. Seeds can also be sown under glass in early spring, where a little bottom heat will induce earlier germination. However, some Clematis are very slow to germinate. Remember that seed saved from your own cultivars may not come true to type. Inter nodal softwood cuttings can be taken of many types in June and July. These are prepared and treated in a similar manner to inter nodal Fuchsia cuttings. Wounding of the lower section below the leaves will increase rooting ability. Some species can be rooted from semi ripe and hardwood cuttings.
Pests and diseases
Aphids (Greenfly) common in early summer, clustering around the growing shoots causing the leaves to curl downwards. Easily controlled by spraying with a suitable insecticide.
Earwigs - night creatures which feast on the sepals and young leaves. These can be controlled by dusting with an insecticide dust, but this can be as unsightly as the damage caused. Place half a grapefruit rind at the base of the plant, and they will cluster here during the night, to be disposed of at leisure.
Slugs & Snails, The bane of the gardener's life, responsible for wholesale slaughter of young emerging shoots. Control by light application of slug pellets.
Mice These can be a nuisance, especially to clematis growing through Heathers, but can be deterred by growing the plant through 12" land drains, which will also provide some initial height.
Mildew, This generally appears on poor starved plants, although some plants are more prone than others. It can be controlled by spraying with a systemic fungicide and paying attention to watering and feeding.
Clematis Wilt, The most devastating disease affecting even healthy well grown plants, causing sudden collapse just as the buds are about to open. Whilst there is no cure, a drench with an approved systemic fungicide at monthly intervals during the growing season does seem to act as a preventative. If, despite this, the disease does strike out the plant at ground level, then again drench the plant with fungicide. Provided deep planting was carried out, shoots should appear at ground level, even several months later.
Varieties
Listed below are a selection of the many hundreds that are widely available from good Clematis growers. The letters AGM at the end of the description refers to the Royal Horticultural Society's Award of Garden Merit, indicating that this is a variety well worth growing.
Evergreen and early flowered species
The Clematis in this section are generally only suitable for the conservatory or nearly frost free conditions. Natives of the Southern Hemisphere, except for Clematis cirrhosa and Clematis armandii, they may be grown in containers and transferred to a greenhouse during severe weather.
Pruning
- remove dead or weak growths and old flowered stems immediately after flowering has finished. Allow new flowering stems to be produced for the following year.
C. armandii boldly handsome evergreen foliage, offsetting in April, swags of dazzling white scented blossoms. It needs a sheltered wall to be successful. AGM. Height 12 - 15ft (3 4 m). Flowering period, March to April.
C. australis a delightful New Zealand species which requires an almost frost free position and is ideal for the conservatory. The small finely cut leaves which are evergreen are offset by tiny creamy green star like flowers which are scented. Flowering period, April to May.
C. cirrhosa (calycina) an evergreen species with neatly cut fern like foliage, producing nodding flowers with four greenish yellow sepals which are freckled inside. Needs a warm, sheltered position. Height 12 - 15ft (3 4 m). Flowering period, January to March.
C. cirrhosa balearica known as the 'Fern leaved Clematis' due to its very finely cut evergreen leaves which turn bronze during winter. Has nodding greenish yellow flowers, spotted reddish purple within. Needs a sheltered position. Height 12 - 15ft (3 4 m). Flowering period, January to March.
C. fosterii a splendid evergreen species, again from New Zealand, it has small leaflets of a pale apple green. The flowers are star shaped and creamy green in colour with a lemon verbena scent. A frost free position is needed for successful cultivation.
C. nepaulensis a species native of the Himalayas and S.W. China. It requires a frost free position except in southern counties. The plant loses its foliage during the late summer and then starts into growth again during late December. The fresh pale green leaves are graced by drooping cream yellow flowers which have long, dark red anthers and are followed by silky seed heads.
C. paniculata another New Zealand evergreen species with flowers 3" across. It has white sepals and pink anthers. Requires a frost free position. Height 10ft (3 m). Flowering period April.
Alpina and Macropetala
This very hardy group are natives of the Alps and China and prove a most successful garden plant. These charming nodding lantern like flowers open during April and are followed by gorgeous fluffy seed heads. Odd flowers are produced during the summer months, Macropetala and Markham's Pink flower during April and early May. They also produce beautiful seed heads and summer flowers. The first flush of flowers is produced from the previous season's ripened stems. This group flowers and grows well if planted in a North facing position.
Pruning
- this consists of removing only dead, weak and unwanted stems which have outgrown the allotted space. This should be carried out immediately after flowering.
C. a 'Charming', vigorous early flowering European species which produces dainty lantern shaped flowers in great abundance in various shades of blue and mauve.
C.a.' Burford White' clear white form has a delightfully shaped flower which stands out against the foliage, very free flowering. 8 - 10ft. high (2 to 3 m.) Flowers in early April.
C.a. 'Columbine' extra long pointed blue sepals. 6 - 8ft. high (2 3 m.) Flowers in April.
C.a. 'Francis Rivis' (Blue Giant) a free flowering clone with extra large light to mid blue flowers. 10ft. high (3 m.). April flowering.
C.a. 'Pamela Jackman' a rich mid blue variety with broad sepals tapering to a fine point. 6 8ft. (2 to 3 m.). April flowering.
C.a. 'Ruby' a profusion of purplish pink flowers in April, often producing more flowers during summer months. 8 - 10ft. high (2 3m.)
C.a. 'Willy' this very pale pink form has a red blotch at the base of each sepal and is free flowering. Blooms in April 6 - 8ft high (2 3- m.)
C. macropetala a delightful species with soft lavender blue semi double nodding flowers followed by masses of fluffy seed heads. Occasional summer flowers 8 - 10ft. high (2 - 3m.). Flowering during April and May. AGM.
C. m. 'Markham's Pink' a charming pink form, associates well with the blue form.
C. m. 'Snowbird' this marvellous white form of the species is slightly later flowering. The elegant semi double flowers are a little smaller than the type plant; a fine new addition to the range.
C. m. 'White Moth' a double white variety whose nodding flowers are most attractive with a pale green foliage. Height 6 - 8ft (2 - 3m). Flowering period April.
Montana types
Clematis montana (a Himalayan species) and its cultivars are sensational and most useful garden plants. Excellent for covering unsightly objects. They may be expected to grow to 20 30ft (7 11m) or even higher if conditions for growth are favourable. If grown through a pine tree a pale pink or white form can look a fantastic sight, like a white or pink waterfall cascading through the dark green foliage of the tree. This group flowers during May and June on old or previous season's stems which have ripened, and occasionally gives a few flowers in late summer.
Pruning
- cut out dead and weak stems and keeping the plant within its allotted space. When growing through a tree, pruning is obviously left to nature. Pruning is carried out immediately after flowering, allowing new stems to be produced for the following season. Not suitable for growing in container, its root system is far too vigorous.
C. montana 'Countless' 2" snow white blossoms with a delicious vanilla scent. Height 20 30ft (6 9m). Flowering period May June.
C. m .'Alexander' a rounded flower 3" across, slightly larger than the type. Creamy white scented flowers. Height 20 25ft (6 7m). Flowering period May June.
C. m. 'Elizabeth' a larger flowered variety with gaps between the four sepals, which are a soft pink. Pleasantly scented. Height 20 30ft (6 9m). Flowering period May June.
C. m. 'Pictons Variety' very deep satiny pink flowers 3" across with four or five sepals. Height 20ft (6m). Flowering period May June.
C. m. rubens a natural variety of C. montana from China, similar in most respects, the flowers are a pale mauve pink, the foliage a much darker green.
C. m. 'Tetrarose' a tetraploid form with large 3" flowers deep rosy mauve in colour, and bronze green foliage. Height 20ft (6m). Flowering period May June.
C. x vedrariensis 'Highdown' the downy bronze green foliage of the hybrid belonging to the chrysocoma group is a splendid foil for the pale pink rounded flowers.
Early large flowered cultivars
The Clematis belonging to this section produce their main crop of flowers on the previous season's ripened stems during late May and June. Assuming that the plant is growing in good soil and conditions are favourable, a second crop of flowers will follow during late July and August on new growth. Watering with a liquid fertiliser will assist to give the extra strength needed by the plant to produce these further flowers. The seed heads from the first crop of flowers are excellent for dried flower arrangements. Most varieties in this section may be planted to face North. If the season should be backward however, the white varieties may open green or with a green stripe down the centre of each sepal. For best effect and depth of colour the pink and pale striped varieties should be grown out of strong sunlight, i.e. North or East facing positions are best. The varieties in this group lend themselves well for enhancing other wall trained shrubs, Pyracantha, Ceanothus, Roses or even fruit trees. Free growing shrubs may also be used, in which case the host and the Clematis can be selected to flower together or before and after one another, thus attaining maximum effect from a small area.
Double and semi-double cultivars
Flowers produced by this group very often appear rather strange when compared with the single varieties, especially when the green outer sepals are present. They are borne on ripened, or previous season's wood, during late May and June, followed by single blooms during August and September. Newly planted Clematis will sometimes produce single flowers for the first couple of seasons. Quite frequently, both double or semi double and single flowers appear at the same time. Due to their top-heavy nature, the varieties of this group are best if allowed to grow through a wall trained shrub or an evergreen, freestanding shrub. If planted facing North, where little sunlight can reach the early blooms, green sepals and on some occasions, totally green flowers may result. A South or West facing position is therefore advisable. Pot or container culture is practicable. If the plant can be well-trained during winter months and brought into the conservatory or sun lounge in April, it will prove a most worthwhile 'pot plant'. After flowering, the plant may be placed in the garden, where normal growth can be continued.
Pruning
- remove dead and weak growth and shorten remaining stems where necessary to a strong pair of leaf axil buds. These fat buds which are visible when pruning carried out (late February, March) are the ones which will provide double flowers. Height 8 10ft (2.5-3 m). If in doubt, don't prune main stems as this will result in only single flowers.
C. 'Beauty of Worcester' deep blue sepals, creamy white anthers, fine fully and double flowers. Flowering period May to June.
C. 'Belle of Woking' silvery mauve rosette shaped double flowers, not free flowering. Flowering period June to July.
C. 'Countess of Lovelace' a most beautiful Clematis, double and single flowers, bluish lilac sepals, cream coloured anthers. Flowering period May to July.
C. 'Daniel Deronda' exceptionally large semi double and single flowers. Deep purple blue sepals, each having a light bar down the centre. Creamy anthers. Specially recommended. Flowering period May to August.
C. 'Duchess of Edinburgh' medium double, white rosette shaped flowers, many sepals having a shade of green. Creamy anthers. Flowering period June to August.
C. 'Jackmanii Alba' rather ragged double flowers of a bluish, skimmed milk whiteness with a hint of green in many sepals. Nicely shaped single flowers with light brown anthers. Flowering period June to August.
C. 'Jackmanii Rubra' attractive double and single flower, the double flowers are not produced freely. Crimson lake red sepals, creamy yellow anthers. Flowering period, June to August.
C. 'Miss Crawshay' pale rosy mauve semi double flowers, light chocolate anthers, the semi double flowers are followed by a crop of single blooms on new wood. Flowering period May June.
C. Royalty - velvety purple-mauve double flowers with yellow anthers. Single blooms in autumn. Blooms in May, June and again in September.
C. 'Vyvyan Pennell' the best and most rewarding double Clematis, with lilac outer sepals and a lavender blue central rosette. Deep lavender blue single flowers. Creamy yellow anthers. Flowering period May to August.
Mid-Season large flowered cultivars
This group produces some of the largest flowers, which can measure up to 10"(25 cm). The flowers are not produced in such abundance as the early large flowered types or the jackmanii types. The habit of the varieties of this group is rather sprawling. The blooms are produced intermittently from late June onwards, usually being stopped by the autumn frosts. It is best to plant this Clematis to grow through large shrubs, where with their open habit they can run riot, displaying their flowers all over their host. Due to its open sprawling habit, this group is not an ideal choice for container culture.
Pruning
- remove dead and weak stems and shorten the remainder to a strong pair of leaf axil buds, during February to March, basically keeping the plant to its allotted space and not allowing it to become bare and untidy at its base. Height 10 12ft.
C. 'Beauty of Richmond' very large flowers, the pale lavender blue sepals shown to effect by the light chocolate anthers. Flowering period, June to August.
C. 'Belle Nantaise' a large handsome flower composed of long pointed lavender sepals and prominent creamy yellow anthers. Flowering period, June to August.
C. 'Blue Gem' a medium-sized flower with pale lavender blue sepals and red anthers forming a rounded bloom. Flowering period, June to August.
C. 'Duchess of Sutherland' one of the largest red flowered Clematis with beautifully shaped tapering sepals and vivid carmine colouring, yellow anthers. Flowering period, June to August.
C. 'Edward VII' quite a distinct and interesting variety. The puce violet sepals each have a pale crimson bar. Light chocolate anthers. Flowering period, June to August.
C. 'Henryii' one of the earliest hybrids to be introduced and still a fine plant. The creamy white pointed sepals are shown to great effect by the dark brown anthers. Flowering period, June to August.
C. 'Maureen' a full flower which is freely dispersed about the plant. Rich purple sepals and green brown anthers. Flowering period, June to August.
C. 'Mrs. Bush' a plant with both large flowers and leaves, not free flowering, yet rewarding. Deep lavender blue sepals and light chocolate brown anthers. Flowering period, June to July.
C. 'Mrs. Hope' large nicely modelled flowers with satiny light blue sepals and red anthers. Flowering period, July to August.
C. 'Prins Hendrich' most beautiful large flowers, the blue sepals have crimped margins. Contrasting red anthers. Flowering period, July to August.
C. 'Fairy Queen' an old variety with flesh coloured flowers, each sepal having a light rosy bar. Light brown anthers. Flowering period, June to August.
C. 'Marie Boisselot' (syn. Madame Le Coultre) large pure white flowers with nicely formed overlapping sepals and yellow anthers. A vigorous and free flowering plant with notably leathery green foliage. Specially recommended. Flowering period, June to September.
C. 'Percy Picton' attractive large flowers, clear intense mauve, brown red anthers. Not a vigorous plant. Flowering period, June to August.
C. 'Serenata' a plant from Sweden, six dusky purple sepals with slightly darker bar are shown to effect by the bright yellow anthers. Specially recommended. Flowering period, June to September.
Pruning
- remove all dead stems, shortening the remainder to a strong pair of leaf axil buds during late February or early March. The fat leaf axil buds which are apparent in early Spring are the ones which will produce the first batch of flowers.
C. 'Barbara Dibley' sumptuous petunia red flowers composed of long tapering sepals, dark red anthers. Best out of strong sunlight. Flowering period May June, August.
c. 'Barbara Jackman' a good striped variety with blue sepals offset by a petunia bar, creamy yellow anthers. Best out of strong sunlight. Flowering period June September.
C. 'Bees Jubilee' a free flowering variety, deep pink sepals with a central bar of brilliant rose madder. Red brown anthers. Flowering period May June, August.
C. 'Bracebridge Star' a star shaped flower with lavender blue sepals and with a central bar of carmine. Red anthers. Flowering period May June.
C. 'Carnaby' this free flowering compact Clematis came from the USA. The sepals are a deep raspberry pink with a deeper coloured bar. The plant is ideal for a shady position and is most suitable for a tub or a patio garden. Flowering period May June.
C. 'Corona' a fine variety from Sweden. The sepals are purple suffused pink with orange highlights, dark red anthers. Free flowering and a compact plant. Flowering period May June, August.
C. 'Dawn'(syn. Aurora) another plant from Sweden, a pearly pink flower, broad overlapping sepals, fading to pearly white, carmine anthers, free flowering and a compact plant. Flowering period May June, August.
C. 'Dr. Ruppel' a very large free flowering hybrid. The rounded flowers have broad sepals which are a deep rose mauve pink, with a contrasting deeper coloured bar, with a central boss of light chocolate coloured anthers. Flowering period May June, August.
C. 'Edith' a free flowering plant retaining the good characteristics of its parent, ' Mrs. Cholmondely'. Pure white sepals and contrasting dark red anthers. Flowering period May September.
C. 'Edouard Desfosse' a compact plant producing masses of rounded pale blue flowers, red anthers. Flowering period May June.
C. 'Elsa Spath' large flowers with overlapping, rich mid blue sepals, red anthers. Rarely out of flower. Specially recommended. Flowering period May September.
C. 'Etoile de Paris' an old variety which produces a compact free flowering plant, pointed mauve blue sepals, red anthers. Flowering period May June.
C. 'Fair Rosamund' an old scented Clematis with white pointed sepals, each with a broad pale pink bar, prominent red anthers. Best out of strong sunlight, not North facing. Flowering period May June.
C. 'H.F.Young' a free flowering , compact plant with Wedgwood blue flowers and pronounced creamy anthers. Flowering period May June, August.
C. 'Horn of Plenty' a large, round flower, rosy mauve sepals which fade to mauve blue with a dark bar. Dark red anthers. Flowering period May June, August.
C. 'John Warren' a free flowering plant which produces sturdy, overlapping pointed sepals with a carmine edge and shading on french grey, giving the flower a dark pink colouring. Red anthers. Flowering period May June, August.
C. 'Kathleen Wheeler' gorgeous plummy mauve sepals with striking golden anthers. Large flowers which are freely produced. Flowering period June September.
C. 'King George V' quite a distinct variety, not free flowering, flesh pink sepals each with a dark central bar, light brown anthers. Flowering period July August.
C. 'Lady Londesborough' a compact, free flowering variety with pale mauve sepals which turn silvery grey. Red anthers. Flowering period May June.
C. 'Lady Northcliffe' a clear shade of Wedgwood blue, white anthers which give a striking contrast. A free and compact flowering plant. Flowering period June August.
C. 'Lasurstern' a most handsome blue Clematis, broad wavy margined sepals tapering to fine points, creamy anthers. Specially recommended. Flowering period May June, August.
C. 'Lincoln Star' eight narrow, pointed sepals of a fresh raspberry pink throughout, dark red anthers. The second crop of flowers are much paler, with a deep pink bar. Flowering period May June, September.
C. 'Lord Nevill' a well moulded flower, bold intense dark blue sepals which have wavy edges, red anthers. Flowering period June August.
C. 'Marcel Moser' inferior to 'Nelly Moser', the sepals finely tapered, light mauve with a deeper bar, red anthers. Flowering period May June.
C. 'Miss Bateman' nicely moulded, creamy white flowers, red anthers. A fine free flowering Clematis of compact habit. Flowering period May June.
C. 'Mrs. Cholmondeley' large light bluish sepals and chocolate anthers. This variety is sometimes criticised because of its gappy, narrow sepals. This criticism is silenced by the profusion of flowers. Specially recommended. Flowering period May September.
C. 'Mrs. N. Thompson' a very colourful Clematis, each sepal comprising a petunia central bar with bluish purple margins. Reddish anthers. Flowering period June August.
C. 'Mrs.P.B.Traux' a compact, free flowering plant with periwinkle blue sepals and creamy white anthers. Flowering period May June.
C. 'Nelly Moser' an old and trusted variety. The blooms which give an appearance of a cartwheel and are produced in abundance consist of pale mauve sepals each with a broad, deep lilac central bar. Red anthers. Specially recommended. Flowering period May June, August September.
C. 'Niobe' the best red Clematis on the market. Its flowers are such a deep shade of red that they stand the strongest sunlight. The plant was raised in Poland and has a strong constitution. The red sepals which are slightly pointed contrast well with the yellow anthers. Flowering period June August.
Pink Fantasy - compact grower, medium sized pale pink flowers. Flowers June-August.
C. 'Richard Pennell' a splendid hybrid with beautifully shaped flowers and rich purple blue sepals. Golden yellow anthers. The anthers have red filaments making a colourful flower. A free flowering plant, strongly recommended. Flowering period May June, August.
C. 'Sealand Gem' lavender sepals each with a deeper central bar, waved edges, light brown anthers. Flowering period June August.
C. 'Sir Garnet Wolseley' an excellent variety which should be more widely grown. Compact and free flowering. Mauve blue sepals with a purplish bar, the flower fades pleasantly. Red brown anthers. Flowering period May June, August.
C. 'Souvenir de Capitaine Thuilleaux' a hybrid of recent introduction which is compact and free flowering. The medium sized flowers have creamy pink sepals with a much deeper pink bar. Best grown out of strong sunlight. Flowering period May June, August.
C. 'The President' a reliable plant which is seldom out of bloom. The rich purple sepals, which are cupped slightly, reveal a beautiful, contrasting silvery underside. Red anthers. Specially recommended. Flowering period May September.
C. 'William Kennett' an excellent old variety with strong lavender blue flowers and handsome red anthers. The sepals are overlapping and have crimped edges. Flowering period June August.
Late flowered species
This group of Clematis and its hybrids are generally extremely vigorous and most useful for growing through trees, very large shrubs or unsightly walls or outbuildings. This group produces its flowers on all new or current season's growth, except Clematis fusca which should be treated as the Montana group, from late July onwards the autumn frosts. Due to their vigorous habit, this group is not suitable for container culture.
Pruning
- reduce all stems to where new growth is visible in February to March. With some of the more vigorous varieties, a pair of garden shears are more practical than secateurs.
C. campaniflora a vigorous species from Portugal which produces an abundance of small bell shaped flowers of white suffused pale blue. Height 15ft (4.5 m). Flowering period, July to August.
C. x durandii (syn. semperflorens) this unusual and alluring Clematis has four deeply furrowed indigo blue sepals and white anthers. Of semi herbaceous habit, it is ideal for growing through a small shrub. Flowering period, June to September.
C. x eriostemon 'Hendersonii' raised at St. John's Wood about 1830. A vigorous semi herbaceous variety of non clinging habit. Masses of indigo blue nodding flowers. Flowering period July to September.
C. fargesi variety 'Souliei' a vigorous species ideal for growing through a green yew tree or conifer. The white inch wide flowers are borne in clusters on long sprays. Flowering period June to September.
C. flammula thousands of small white starry almond scented flowers. It can look marvellous if allowed to grow through a green holly tree, a vigorous and attractive European species. Height 10 15ft (3 4 m). Flowering period August to October.
C. florida 'Sieboldii' (syn. bicolour) perhaps the most fascinating of all, and often mistaken for the Passion Flower. The growth is slender to 8ft. Flowers are 4 inches across, broad white sepals framing a domed central boss of rich purple petal like stamens. Needs a sheltered position. Flowering period June to September.
C. 'Alba Plena' an all white form of Clematis florida bicolour also requiring the protection of a warm sheltered wall. Flowering period June September.
C. glauca this species belongs to the orientalis type, its glaucous, finely cut foliage is interesting. The nodding orange yellow flowers are freely produced on long stalks. Flowering period August to September.
C. x 'Huldine' an excellent variety with exquisitely shaped flowers, pearly white above, mauve beneath. A profusely vigorous plant. Flowering period July September.
C. x jouiniana a very vigorous hybrid (Clematis heracleifolia Davidiana x Clematis vitalba). Non clinging, producing many small, soft lavender Hyacinth like flowers. Useful for covering larger tree stumps or low fences. Semi herbaceous. Flowering period August September.
C. 'Praecox' an earlier flowering form of the species above, slightly larger flowers.
C. maximowicziana a vigorous species with hawthorn scented white blossoms. Flowering in the autumn only after a hot summer. Height 20ft (6m). Flowering period September October.
C. orientalis 'Bill Mackenzie' this hybrid has the largest flowers of the orientalis forms. The 2" long cow bell like deep yellow flowers are followed by large seed heads.
C. 'Burford Variety' a natural seedling bearing the characteristics of both Clematis orientalis and Clematis tangutica. An extremely vigorous plant with fine cut foliage and a profusion of deep yellow nodding flowers. The sepals are as thick as lemon rind. The flower is less open than the type. Flowering period August to October.
C. 'Corry' a hybrid from Holland with pale yellow lantern like flowers.
C. 'L & S 13342' a species from Tibet with delicately fine cut foliage, offsetting a continuous succession of nodding ochreous yellow cowbell like flowers, each sepal as thick as lemon rind. Vigorous once established. Does not like extremes of drought or moisture. Flowering period, August to October
C. rehderiana (syn.nutans) a really vigorous species from Western China, with masses of coarse foliage. Loose clusters of little bell flowers of dingy yellow, but with a heavenly airborne Cowslip scent. Ideal for growing through a large tree. Flowering Sept Oct.
C. serratifolia similar to Clematis orientalis. A Korean species with pale yellow nodding flowers with purple centre. Unusually vigorous, making a fine ground cover plant. Flowering period, August to September.
C. tangutica a rampant species from China and a fine sight when billowing with feathering seed heads and yellow lantern flowers, all at the same time. Height 15 20ft (5 6m). Flowering period, July to September.
C. texensis this is the scarlet flowered Clematis from Texas, which in nature usually dies completely back in winter. Hybridisation of this species with large flowered varieties has given rise to a number of beautiful Clematis having erectly held flowers, somewhat resembling small Tulips. We list these hybrids below. They are ideal for training over low growing shrubs or among the winter and summer flowering Heathers. The whole of the spent growth may be cut right back in autumn or early spring.
C. 'Duchess of Albany' soft warm pink with a cherry red central band. Height 8 10ft (3m). Flowering period August to September.
C. 'Gravetye Beauty' glowing ruby bells, gradually expanding to a star shaped flower. Height 8 10ft (3 m). Flowering period August to September.
C. 'Pagoda' this charming hybrid was raised by Treasures of Tenbury. The pale pink mauve nodding flowers have sepals that recurve at the tips.
C. 'thibetianus' this splendid glaucous foliaged species of recent introduction is a strong growing plant. The most attractive foliage is offset by delightful nodding yellow green flowers which have recurving tips to each sepal.
C. 'x triternata 'Rubro marginata' (syn.flammula Rubro Marginata) the result of a cross between Clematis flammula and Clematis viticella. Small star like flowers, each sepal margined with reddish violet. The blossoms are freely produced in billowing clouds. Height 15ft (5 m). Flowering period, August to September.
Viticella types
Clematis viticella is a vigorous species from Europe and was introduced to England during the 16th century. Since then, it has given rise to many fine varieties and hybrids, some of which are listed below. The group is most useful in a small garden. It looks splendid when its semi nodding flowers come tumbling down from a low forking tree, or scrambling around at ground level through the many ground cover plants. Possibly one of the best host plants is the winter flowering heather which gives a light green carpet after flowering to show off the bright colours of this group during July, August and September. The summer and autumn flowering varieties of heathers also make excellent host plants. All the Clematis top growth should be removed during late October to allow the heathers to produce their own flowers freely. A selection of these should be planted for the effect, and about 5ft(1.5 m) apart. The viticellas are not suitable for container culture due to their vigorous and leggy habit.
Pruning
- if the Clematis is to be trained upright, prune during late Feb/March. Reduce all stems to strong buds, a few inches above the base of the previous stems.
C. viticella this type of plant has mauve purple nodding flowers, produced in great abundance on dainty flower stalks. 10ft. (3m.) July September flowering.
C. 'Abundance' abundant flowers of wine rose with deeper red veins. 10ft. July/Sept.
C. 'Alba Luxurians' a mass of creamy white, green tipped sepals, which twist and reflex, dark anthers. Height 10ft(3m). Flowering period July September.
C. 'Etoile Violette' medium sized violet flowers(3") with creamy anthers, vigorous and very free flowering. Height 10ft (3m). Flowering period July September.
C. 'Madame Julia Correvon' an old and beautiful variety with delicately poised, wine red flowers composed of four to six rather narrow and twisted sepals recurved at the tips. Height 6 10ft (2 3 m). Flowering period, June to September.
C. 'Margot Koster' a gappy flower with rosy eyed sepals producing a mass of blossom. 6 8ft. (2 3m.) July August.
C. 'Minuet' abundant semi nodding flowers. Sepals white with mauve veins and margins. 10ft. (3m.) July August.
C. Purpurea Plena Elegans this delightful old double form of viticella produces an abundance of rosette shaped flowers with violet sepals. 10ft. (3m.) July September.
C. 'Royal Velours' the flowers of this variety are so deep in colour a light background is essential to show the plant to its best advantage. The deep velvety purple sepals form a rounded full flower. Height 10ft (3 m). Flowering period July to September.
C. 'Rubra' a real eye-catcher. Quantities of wine red flowers with dark centres. Height 10ft (3m). Flowering period July to August.
C. 'Venosa Violacea' the 4" wide flowers consist of five or six boat shaped sepals, deep purple at the margins, almost white at the centre and overlaid throughout with a network of purple veins. Height 10ft (3 m). Flowering period. June August.
Herbaceous types
The herbaceous Clematis are normally planted in the herbaceous or mixed borders. The blue flowers of integrifolia and the heracleifolia group can be most attractive when planted in rose beds or in association with the perpetual shrub rose. It is difficult to stake these plants successfully, they are best left to sprawl among low and taller growing plants.
Pruning
- remove all top growth when convenient from Nov. until the end of February.
C. douglasii var. scotiae a most interesting herbaceous Clematis from the USA. Glaucous foliage pitcher shaped blue mauve flowers produced on long stalks. Large fluffy seed heads. 2ft. (0.6m.) Flowers in July August.
C. heracleifolia a deciduous sub shrub from China bearing axillary clusters of hyacinth like flowers on woody stems. This has produced several variants some are listed below.
C. 'Cote d'Azur' neat 2.5ft. stems, pale blue hyacinth like flowers. 3ft. (1m.) August September.
C. 'Davidiana' 3 4ft stems bearing clusters of deliciously scented Hyacinth like blue flowers. Height 3ft(1m). Flowering period August September.
C. 'Wyevale' large fragrant flowers of a deep Hyacinth blue. Flowers August October.
C. integrifolia a European herbaceous species, nodding indigo blue flowers. 2 3ft. Flowers in July. 'Hendersonii' a larger form of the integrifolia.
C. 'Olgae' sepals clear pale blue, rather more twisted than the type. Deliciously scented.
C. 'Rosea' a sugar pink form, looks fine when blue and pink forms are grown together.
C. 'recta' herbaceous species, matt green foliage, with a galaxy of small white blossoms. Sickly sweet scent. Height 4 6ft (1.5m). Flowering period June July.
C. 'Purpurea' this form resembles the foregoing in every respect except that its foliage is of a purple bronze colouring. Height 4 6ft (1.5 m). Flowering period June July.
Sources of Supply
- This list includes a few of the many Clematis stockists :
Ashwood Nurseries offer a very wide range of Clematis from several different growers around the country
Hawthorne's Clematis Nursery Holder of the National Collection of Texensis group, Viorna group and the Viticella,s this company offer a wide range of Clematis and other plants.
Raymond Evison Clematis Has an excellent website with links to local stockists near you plus superb growing guides
Priorswood Clematis Good reputation and based in Hertfordshire
Taylor's Clematis must be one of the best sites for information about Clematis as well as purchasing [plants
Thorncroft Clematis and Climbers A very good supplier with excellent customer service
Further reading
Making the Most of Clematis by R. Evison published by Floraprint.
Clematis published by the RHS in their Wisley Handbook series.
The information given in this Fact Sheet is provided in good faith. It is however of necessity general information and advice on the topic. Howard Drury will not be under any liability in respect of the provision of such advice and information and you are strongly advised to seek independent advice on any particular gardening problems or queries you may have, preferably from experts who can (when appropriate) inspect the problem before providing advice.
(C) 2022. This material has been produced by Howard Drury and must not be reproduced in part or full physically or electronically without the written consent of Howard Drury, Kings Heath Birmingham, B13 0SJ. The only exception be to print a single copy for personal use from a downloaded file as part of the drurys website. Visit www.thedrurys.com or email
JHD/20/022022
