Family: Ranunculaceae
Common Name: Traveller's Joy, Virgin's Bower

There are at least 200 species and countless hybrids of clematis, mostly from the northern hemisphere, with a few native to the southern hemisphere, including Australia and the Pacific region. Clematis often climb high into trees from which their flowers tumble out over the canopy so are useful for covering free-standing arches or walls. If planted under the right conditions and well cared for, clematis are reasonably fast growing and long lived. Most clematis plants produce blooms within the first couple of years after planting. Some flower in spring only, and others flower either throughout spring and summer or during summer and early autumn. The large-flowered, deciduous forms known as Jackmanii hybrids have been developed from several species and have some of the most spectacular flowers imaginable. They come in a great range of brilliant, single colours-white, blue, purple, crimson and cerise-as well as bicolours.

Species

C. alpina, zone 5, native to Europe and Asia, grows vigorously to 2 m (6 ft) and produces small, violet-blue, lantern-like flowers in the spring. Cultivars include 'Columbine', with pale blue flowers; 'Pamela Jackman', with deep blue flowers; and 'White Moth', with white flowers.

C. aristata, old man's beard or goat's beard, zone 7, is an Australian species found growing in moist, sheltered areas where it loves to clamber up into trees or over old stumps where its fragrant, white, starry flowers are best displayed. The spring and summer flowers are followed by fluffy white seed heads, which persist for several months, becoming fluffier as they mature. The species is variable, and there are many forms.

C. armandii, from China, grows to 5 m (16 ft), with evergreen foliage and small, fragrant, whitish flowers.

C. flammula grows 2-5 m (6-16 ft), with fragrant, white flowers late in the season.

C. foetida, zone 8, from New Zealand, produces an abundance of fragrant, greenish yellow flowers in long sprays from spring to early summer. 'Jackmanii' and other large-flowered hybrids sometimes reach 3 m (10 ft) in height and produce by far the largest flowers of all the cultivated clematis. 'Barbara Jackman' has blue-mauve flowers; 'Comtesse de Bouchaud' has mauve-pink flowers; 'Gipsy Queen' has purple flowers; 'Lady Betty Balfour' has blue-purple flowers; 'Jackmani Superba' has purple flowers; 'Lincoln Star' has raspberry pink flowers; 'Nellie Moser' has mauve and carmine flowers; and 'Perle d'Azur' has light blue flowers. Many others are also available.

C. macropetala, zone 5, from Asia, reaches 3 m (10 ft) high and has small, lantern-like, double violet flowers in spring. Cultivars of this species are available.

C. montana, one of the best known species, is a vigorous, deciduous vine from the Himalayas, with small, white flowers. Var. rubens is also widely grown.

C. recta, zone 3, from Europe, is a herbaceous plant, to 2 m (6 ft), which hears profuse, fragrant white flowers. 'Purpurea' has purple leaves.

C. rehderiana, from China, grows to 6 m (20 ft) in height, with fragrant, straw yellow flowers.

C. stans, zone 4, from Japan, is a late-flowering, herbaceous type, to 2 m (6 ft), with blue flowers.

C. tangutica, from Asia, bears bright yellow, bell-shaped flowers late in the season and grows to 3 m (10 ft).

Cultivation

All clematis like a well-drained soil enriched with decayed organic matter. Often described as needing a 'cool root run', they need soil that remains cool and moist at all times. It is important to give regular, deep watering during spring and summer.

C. aristata and C. pubescens prefer dappled sunlight; most others prefer full sun but will tolerate semi-shade in cool climates. Feed in spring, as growth starts, with complete plant food and a dressing of well-rotted manure. These twining climbers are happy with any sort of support, for example a tree, pergola or lattice.

The timing and method of pruning depends on the species or cultivar grown. Some pruning may be needed to train these climbers to their structures or supports. Many of the Jackmanii hybrids should be pruned in late winter, just before new growth commences. However, sometimes it is best to leave them until they have filled their allotted space. Some should be pruned only very lightly. Ask the local nursery, or refer to the plant label, if in doubt.

C. montana flowers on the previous season's growth, so pruning should be confined to the removal of spent flowers and directional cutting to restrict size if necessary. Very old vines may require the removal of old canes at ground level to make way for younger, more vigorous growth. Propagate species from seed and cultivars from softwood cuttings in spring, rooting them under glass. All can be grown from stems layered to the ground in spring ready for cutting and lifting at the end of the following winter. Some hybrids can be grafted, though suitable species understocks must be used. This is usually not an option for home gardeners.

Climate

A great many clematis, including the large-flowered hybrids, are suited to zone 6.