Top Tips For Success With Clematis

We met Clematis expert Ray Evison to find out his top tips for clematis success.

Andy:

No one knows more about growing Clematis than Ray Evison. Many times an RHS Chelsea Flower Show Gold Medal winner, Raymond has bred show-stopping varieties, some of which we’ve featured on this blog.

However, what I want first and foremost are Raymond’s top tips for success with these wonderful climbers. They don’t always thrive on my light, sandy, slightly acid soil. Is that the problem? What should I do to make sure they grow and bloom at their best?

Raymond:

Clematis must have a cool root area to grow well. Always plant shallow rooted perennials or seasonal bedding plants around the base of a clematis to shade the roots of the plant.

This is particularly important when growing them in containers, or when the clematis is planted in a sunny location. Do not use stones or pieces of slate, which are often recommended, as these retain warmth and can heat up the ground, rather than keeping the roots cool.

Clematis like to grow in a garden as they do in the wild: in a micro-climate with other plants. Do not plant a clematis on its own to grow up a bare trellis against a wall or on a wooden fence. Plant another wall trained shrub, rose or other climber and then grow the clematis through the host plant.

Doing this gives the maximum benefit in growing conditions and decorative effect. The foliage and flowers of the host plant are a foil for the clematis. Also the clematis may flower when the host plant is perhaps not looking its best.

Some pale flowered clematis fade in strong sunlight. Use varieties with pale blue, pale pink, or other pastel flowered clematis in shady positions. They will not fade and more importantly they will brighten up a dark or shaded area. As long as the clematis have 3 to 4 hours sunlight a day, not necessarily direct sunlight, they will grow and flower well.

Use the red, deep blue, white and purple flowered clematis in sunny locations. They are unlikely to fade and often the colours become even stronger in direct sunlight.

Feed clematis with a high potash, high nitrogen fertiliser. Rose fertiliser is ideal in spring and again in midsummer. For an extra boost use tomato fertiliser during the growing season. This is ideal for clematis growing in pots and containers.

Always plant a new clematis an extra 7-8cm (2-3 ins) deeper than the growing medium level in the nursery pot. Whether you are planting it in the ground or in a larger pot or container.

This helps the plant to recover if it is damaged; perhaps eaten by mice or rabbits at the base, or if it suffers from clematis wilt. By planting that bit deeper it will form a root crown below soil level, and will therefore regrow from below soil level if it is damaged. This is particularly important with the large flowered varieties.

Clematis pruning can be really confusing. Today plant labels give a good indication of how and when to prune. You can also check on the internet or in a good reference book. A good guide is to remember that the later a clematis flowers in the year, the more pruning it needs. So generally clematis that flower in spring need little or no pruning at all. Hence the saying: “If it flowers before June, don’t prune”.

However, whatever the pruning requirements: any clematis should be pruned very hard the first spring after it has been planted. In the first spring, just before the plant starts to grow, cut all stems back to 15-20 cm (6-8ins) above soil level. This will encourage branching and help to cultivate a plant which is bushy at the base.

Andy:

Some great tips there and I’m pleased to hear that clematis like to grow through other plants. I have little in the way of walls and fences but plenty of shrubs that will benefit from another season of interest by the addition of a clematis.

These are such useful plants and the great thing is how easily they fit into any garden, whether you have a courtyard or estate.

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Climbers & Clematis

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Climbers & Clematis taught by Pip Bensley

Choose the right climber for your garden with advice from Pip Bensley. Pip will cover everything from plant choice, maintenance and colour combinations right through to pruning techniques.

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