Large-flowered hybrids are the best known representatives of the species clematis. They are appreciated for their magnificent, large flowers (considerably larger than 10cm in diameter) and for their long flowering period. There are hundreds of cultivars, but they are more or less susceptible to diseases and need care. These hybrids can be used to green facades, as they grow up to 3 metres high. Varieties that flower even when they are still very low are particularly suitable for potting on the balcony. Available varieties and prices can be found in the overview.
These clematis do not like hot southeast or west oriented walls, and need a partially shaded location. Many cultivars, such as Dr. Ruppel and Nelly Moser, need full shade. The location must be wind protected and the stem base shaded. The soil should be fresh and well-drained -- standing water should be avoided at all costs! The planting distance is between 0.5 and 1.5 metres. When planting, position the roots 10cm below the surface. If potting your clematis, choose a pot size of at least 12 litres. For available varieties/prices, see the overview.
Clematis are frost-resistant, perennial leaf-stem (petiole) climbers, with weak to medium growth strength. Foliage develops from May to October and is not very dense. Growth height between 2 and 4 metres. Flowers open in May / June. If the flowers are consistently cut off and the soil is fertilised, there might be a second flowering in August / September. There are beautiful seeds in autumn, but the old leaves don't really fall off by themselves and will need to be cut. Cut all shoots to half length at the end of the year.
Large-flowered clematis hybrids are prone to mildew and clematis wilt. Mildew can be prevented by choosing healthy cultivars and a good planting spot. Proper watering is crucial: the leaves should never get wet (just as with tomatoes). As to the dreaded clematis wilt-- all varieties that will flower multiple times and those that flower early are more vulnerable than late summer bloomers, such as the Ernest Markham.
A close-meshed arrangement with grid 'squares' 20 to 30cm is optimal. Vertical axes should dominate to create 'standing rectangles' rather that squares. See the table of suitable cable systems at the bottom of this page. Our wire rope trellis design 5050 with steel rods is a good choice-- in the easy or light version or with a medium version for optimal development of the plant. Heavy / massive designs are further away from the wall and can be chosen if the risk of mildew is high.