Clematis, also known as traveler’s joys, are flowering climbing shrubs, but are considered somewhat sensitive. Wrongly so: with these care tips, nothing will stand in the way of a flowering festival that will last for years.
Clematis are among the most beautiful and popular climbing plants in the garden. From planting to fertilizing to pruning: if you take these tips to heart, your clematis will feel completely at home.
The ideal location for clematis
In nature, the wild species of clematis grow mostly on sunny forest edges or in clearings. In garden forms, flower size and color have changed, but not location requirements: they also prefer a semi-shaded location with morning and/or evening sun and a cool, shady root zone. Simply plant a few ferns or large-leaved woodland perennials such as funkias or Rodgersia around the clematis.
Optimally fertilize clematis
As far as fertilizing clematis is concerned, traveler’s joys get by with quite few nutrients. In their natural habitat, they also rely on what microorganisms release from autumn leaves and other dead plant parts. Therefore, it is quite sufficient to provide clematis with two to three liters of mature compost once in spring. Most wild species also have a somewhat higher lime requirement: simply sprinkle a handful of garden lime or algal lime in the root area every two years in winter.
Prevent ring rot disease
Large-flowered clematis hybrids, such as ‘Niobe’ suffer more often from clematis ring rot disease. The fungal disease causes the above-ground part of the plants to die completely. Apart from the right choice of location and good soil preparation, the only thing that helps is regular control, especially in the summer months. Immediately cut off infected plants close to the ground, they usually resprout if planted deep enough.
Planting clematis properly
It is important to have a deep and humus-rich soil, which should be as evenly moist as possible, but not too wet. Therefore, work in a generous amount of mature leaf compost and potting soil before planting the clematis. In impermeable, clayey soils, a layer of building sand at the bottom of the planting hole will protect the delicate roots from waterlogging. You should plant large-flowered clematis deep enough so that the first pair of buds is below ground level. This increases the chance that the plants will resprout from below after a ring rot disease attack.
The right climbing aid
The climbing ability of all clematis species is based on leaf tendrils, the extended leaf stems wrap around the climbing aid and in this way fix the thin shoots. The ideal trellis for clematis therefore consists of the thinnest possible, mainly vertically positioned rods or battens.
Clematis and climbing roses
Climbing roses and clematis are considered the dream couple for the garden. For them to develop equally well, however, some know-how is required: plant the rose one to two years before the clematis, if possible, and separate the root spaces of the two plants in the middle with a root barrier, such as a thin wooden board.
Be careful when preparing the soil
Like most woodland plants, clematis have a fine root system that is close to the surface. Therefore, you should refrain from any form of tillage in the root zone of the plants. It is best to regularly pluck out unwanted weeds by hand, and a mulch layer of pine bark will help prevent this. You should also avoid damaging the thin shoots, as this increases the risk of infection by ring rot disease.
Wild clematis species are particularly robust
The wild species and their selections, such as the golden clematis (Clematis tangutica), are generally more vigorous and less susceptible to disease than the cultivated large-flowered hybrids. Nevertheless, you don’t have to do without magnificent flowers, there are now numerous colorful garden forms of the Italian Clematis (Clematis viticella), for example. They bloom profusely and, depending on the variety, their flowers are only slightly smaller than those of the clematis hybrids.
This helps against flowering problems
If the flowering of clematis is rather sparse, it is often due to a lack of light, for example, under a tree canopy. If the flowers remain small, lack of water is usually the cause. A greenish sheen on the flowers, luxuriation, occurs with potassium deficiency and low temperatures. In some Viticella forms, however, it is a characteristic typical of the variety.
Pruning clematis for more flowers
Varieties of Italian clematis, as well as all other pure summer-flowering clematis, are pruned back to just above the ground in spring. Clematis hybrids that are blooming a second time are given a lighter pruning in spring so that the first bloom in late spring or early summer is not too sparse.
When pruning clematis, keep in mind that clematis varieties are divided into three pruning groups based on their blooming season. Pure summer bloomers are pruned to about 30 cm (12 in) in height in the spring. Wild species that bloom in spring can usually do without pruning. Some large-flowered hybrids bloom in spring on old wood and in summer on new wood. With light pruning in spring, you encourage the first bloom, with heavy pruning, you encourage the second bloom in summer.