Clematis species and cultivars offer early-flowering, early, large-flowered and late-flowering species and cultivars as a climbing plant. Best positioned on a south-facing wall or garden structure, Clematis armandii and Clematis montana offers a sound selection for hardiness in cold winter. Clematis montana can climb 7 to 12 meters to cover arbours and walls. The Royal Horticultural Society Encyclopedia of Gardening has a helpful chapter on Climbing Plants, that reports that there are three distinct groups of clematis.
Early-flowering Clematis species
The first group of clematis are vigorous plants requiring little, if any, regular pruning. They are an ideal first time climber and an interesting introduction to growing clematis. New clematis bought in pots will need planting in top dressed soil and to be tied into a suitable support. The reward of early flowers and relatively low maintenance for the planter means easy gardening, once positioned, planted and watered in.
Early-flowering species are Clematis alpina, Clematis armandii, Clematis cirrhosa, Clematis macropetala, Clematis montana, Clematis montana var. grandiflora and Clematis montana var. rubens (pink and white flowers)The new growth of these clematis climbing plants will ripen during late summer and autumn and provide flowers the following spring.
Early, Large-flowered Clematis cultivars
Cultivars such as Clematis 'Barbara Jackman', Clematis 'Carnaby', Clematis 'Daniel Deronda', Clematis ' Duchess of Edinburgh', Clematis 'Lincoln Start', Clematis 'Niobe' and Clematis 'Vyvyan Pennell' have characteristic solitary flowers. These large flowers are produced on stems of lengths from 15 centimeters to 60 centimeters, from last season's growth. Clematis 'President' makes a statement with purple flowers. Lovers of pink and white should select Clematis 'Nelly Moser' with its eight petal head large flower with distinctive pink swoosh in the center of the white petals.
Late-flowering Clematis species and cultivars
A third group of clematis species and cultivars produce flowers on this year's growth. The selection of late flowering clematis climbing plants include Clematis ‘Comtesse de Bouchaud’, Clematis ‘Duchess of Albany’, Clematis ‘Etoile Violette’, Clematis florida, Clematis ‘Hagley Hybrid’, Clematis ‘Huldine’, Clematis ‘Lady Betty Balfour’, Clematis ‘Perle d’Azur’, Clematis ‘Star of India’, Clematis tangutica, Clematis ‘Ville de Lyon’ and Clematis viticella. Planters desiring strident colors for planting schemes will find Clematis 'Madame Julia Correvon' and Clematis 'Ernest Markham' offering vibrant red. Alternatively for a premium purple color and small flowers, Clematis 'Jackmanii' in this clematis group is suitable for growing through other climbing plants such as roses.Planter beware - as these clematis can make a delicate and temperamental climbing plant. New stems of Clematis florida and similar late-flowering clematis are often soft and brittle.
Pests and Diseases of Clematis
Clematis with fresh young growth is attractive to slugs in early spring. Aphids can be a pest and the large flowered cultivars may get powdery mildew. Fungus attacking newly planted, large flowered clematis can cause clematis wilt and failure to thrive.
Buying a Clematis Plant from Nurseries or Garden Centres
Clematis are usually sold to the public as container grown plants. Buyers are advised to check the pot to select the most promising plant. Turn the pot over and if the tips of the young roots are just showing, then the plant is well rooted. If a mass of roots have grown through the pot's drainage holes, then this plant is pot-bound. Even if the clematis looks attractive and flowering in the pot, being pot bound means that the plant is highly unlikely to grow well in your backyard garden.
Source:
Brickell, C (Ed) (2007) The Royal Horticultural Society. Encyclopedia of Gardening. London: Dorling Kindersley.
Susan Morris - Susan Morris, Scottish food and drink business manager, organic gardener, author and editor
