Clematis in Containers

Clematis actually feel happiest when planted in the open ground - after all, they are climbing plants. However, balcony and roof-terrace gardeners will be glad to know that clematis are an incredibly versatile group, and many varieties thrive in a planter.

1. The right variety for the container

In principle - given a suitable container - all clematis varieties would feel at home in it. Realistically, though, these are mainly herbaceous clematis, hybrids that grow more shrubby and bushy than climbing, and the abundantly flowering Italian clematis (Cl. viticella), which also do well in a container. Keeping a mountain clematis in a pot would be a greater challenge, both for the container itself and for care and winter protection.

That leaves you with several dozen varieties for containers; where we consider a variety particularly suitable, we have noted it in the variety description. In general, trial and error is the best teacher, but please do not choose the largest varieties of each group without a good reason - such as having an extremely large pot.

2. Finding the right container

The container must be large enough, both for the chosen variety and for the number of plants if you want to plant several clematis together.

With clematis the shape of the pot matters less; find the right pot size by volume - 20 litres should be the minimum. For less vigorous herbaceous clematis, smaller pots with less soil are also possible.

Another important point is drainage. Clematis hate waterlogging and respond with reduced growth, sudden wilting and other unsightly signs. The container should therefore have sufficiently large drainage holes. Above these goes a drainage layer of stones, pebbles, pottery shards or similar.

3. Several clematis in the same pot

Attractive combinations of several clematis, or of clematis and roses, are possible. If a rose is part of the planting, the planter must also be sufficiently deep.

Otherwise, you can use roughly 10 litres per clematis plant as a rule of thumb.

4. Climbing supports for clematis in containers

Apart from low-growing, self-supporting herbaceous clematis, the plant needs something to support itself on, even in a container.

One option is to use existing structures outside the container. These can be fences, walls, existing wall trellises or other plants. In this case the container is simply placed in a suitable spot.

For a free-standing arrangement, a support must be placed in the container. The simplest option is to anchor a pyramid of three bamboo canes in the soil. Smaller obelisk-like metal structures can also be fixed in the container, provided they fit.

Creative gardeners with manual skill have come up with the most astonishing creations here - if you know of one, we would be glad to receive an e-mail with a picture.

In any case it is important that the support is stable enough for the expected growth of the clematis and any other climbers growing on it - even under load during a summer thunderstorm or after heavy rain.

4. Overwintering clematis in containers

Unlike plants growing in a bed, plants in pots are exposed to greater stress in winter. The soil in the pot freezes faster, which means the entire root system may be exposed to very low temperatures.

Sensible winter protection can consist of wrapping the pot with a sufficient air cushion. The pot is often also placed on a polystyrene board so that the cold cannot penetrate from below as easily.

Another measure is to change the container's location over the winter months. Here the aim is to avoid the combination of sun, cold and possibly wind (= bare frost). Garden sheds, sheltered corners of the house, unheated garages or simply sheltered corners of the garden or terrace are good options during the cold season.

If it is not possible to move the container with its clematis elsewhere in winter, you can also provide shade, for example with fleece, bamboo mats or similar.

During very long, dry and simultaneously cold periods (easterly weather with biting cold) you should water a little now and then - even if the soil is frozen.

5. Providing enough nutrients

Especially because a plant sitting in a closed container does not have comparatively many nutrient resources from the open ground, fertilising container clematis is particularly important.

6. Keeping an eye on moisture

Because of the limited soil volume in the pot, you will have to water more often than elsewhere in the garden. Keep an eye on your clematis on the balcony and terrace; they signal a lack of water very quickly through rather limp-looking leaves and flowers.

Someone should take responsibility for your plants during the summer holiday - even if you have delegated the task to an irrigation computer.

Clematis do not like too much moisture; standing water should be avoided. The drainage should therefore be checked regularly, and at the latest when problems become visible.

7. Planting the clematis in the container

How to pot a clematis and what to bear in mind is explained here.

8. Pruning in the container

There are no differences here compared with clematis planted in the open ground. On a separate page you will find how clematis are pruned. In this situation, early-flowering hybrids benefit particularly from a summer pruning, which promotes the second flowering period.

9. A change of scenery

After several years in the same container, or when the clematis stops growing or flowering, it is advisable to rethink the situation.

A complete replacement of the potting substrate in autumn - or at least outside the growing and flowering seasons - works real wonders. The clematis roots are freed almost completely from the old soil, cut back sharply and shortened by about 1/4.

Sometimes clematis simply do not like the location. If your containers are movable you are in luck and can simply place the pot 'around the corner'. Sometimes changed light conditions and a slightly different microclimate are enough to turn a struggling container plant into a real feast for the eyes.

Another problem can be that the chosen variety turns out not to be as well suited to permanent pot culture as hoped. In that case the only real option is to release the clematis into the open and look for a suitable spot in your own garden or with friends.

Tip: The container does not have to be a permanent solution. Savvy gardeners also deliberately use container culture as an intermediate stage to find the optimal spot for planting in the open ground. The container can also be buried up to its rim, which keeps maintenance low while still retaining a degree of mobility during flowering.

Do you have questions, suggestions or experiences to share about this article?

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