Growing Clematis in Containers
Growing clematis in containers is easy if you choose the best variety and use the right materials.
I’m often asked to recommend a climbing plant to train up the front of a house. At this stage I’m thinking of how I’m going to narrow down the choice since there are hundreds of varieties!
Then I ask how good the soil is and the reply I get is ‘there’s concrete right up to the wall’ and alarm bells start to ring! Why is it that so often every inch is concreted or paved over?
Now most climbers can cope with limited root run and so growing them in containers of some kind or other is the answer. That is, until the climbing plant gets big! Then their growth will be severely limited by how often you remember to feed and water them. The answer is to choose your plants carefully and use big containers!
Even before the advent of container grown garden plants in the 1960s Clematis were grown in pots. But some Clematis varieties are clearly much more suitable to spend their whole life in a pot than others.
Before we look at those, how about getting the container and compost right for growing clematis in containers?
Pots and Containers
I’ve already suggested that big is better and if, when you plant a new clematis into a big pot it looks a bit lonely, plant some annuals in there with it! For a year or two this will be possible but soon your clematis will need all the root run it can get and you then stop adding the annuals.
Clematis in containers prefer a pot that isn’t subjected to wild variations of temperature. That rules out thin walled plastic containers for me. But recycled oak barrels or glazed pots work well. In these the roots are kept cooler in summer but also insulated from all but the hardest frost in winter. If space for containers is limited then add volume by spreading along the wall using trough shaped containers.
Potting Composts for Growing Clematis in Containers
Soil based potting compost is best for growing clematis in containers. However John Innes No.3 compost can be improved by adding 50% by volume of a peat free compost to it. This will ‘open up’ the structure and a lead to a healthier root system.
Feeding Clematis in Containers
I like to add granular controlled release fertiliser to the compost. This gives a steady supply of nutrients over a whole growing year. For the subsequent years I just add it to the top of the container every spring. Osmocote or Westland Gro-Sure 6 Month Slow Release Plant Food is perfect.
Choosing suitable varieties
There are lots of suitable varieties. Look for those that are compact growers and flower well down the stem. Those bred by Raymond Evison on Guernsey are especially suitable. He doesn’t sell his varieties direct to consumers but instead supplies growers with young plants that they then grow on to sell through all good garden centres.
In respect of extending the flowering season; try growing an early bloomer with one that blooms later. If that doesn’t appeal then have fun teaming different colours together so that their blooms contrast or complement one another! I’ve had the large flowered varieties ‘H F Young’ and ‘Asao’ together in an oak half barrel for years and they just keep on going with regular water and feed. There is no end to the variety options that you could use instead!
But, if you are confused by all the choice, and if you really want the best performance anyway, you need to plant those Raymond Evison varieties! Raymond has spent a lifetime breeding clematis so that they flower repeatedly and flower all the way down the stem. You won’t go wrong with any of his varieties and he has done to clematis what the late David Austin did to roses. He has looked at the old varieties and their failings, and then bred to cancel these weaknesses out.
Some Recommended Varieties
So okay, from all the hundreds of varieties available I’m going to recommend a few favourites of mine but these are by no means the only clematis to grow in containers!
Avalanche – a really early small flowered white
alpina – all varieties
macropetala – all varieties
florida Alba Plena – complex passion-flower like blooms, needs warmth.
Bees Jubilee, Dr Ruppel, Nelly Moser – large pink bicolour blooms.
General Sikorski, Prince Charles, Perle D’Azur, Lasurstern – soft blue
Marie Boisselot, Edith, Duchess of Edinburgh – large whites
Niobe, Warsaw Nike, Kermesina – rich red to claret
And from Raymond Evison’s breeding –
Crystal Fountain – lilac blue double blooms
Bourbon, Rosemoor or Rebecca – red
Piccardy – violet blue
Pistachio – creamy white
Josephine – pink mauve double blooms
And finally the one that sums it all up if you get it right – Ooh La La – a lovely pink with a darker bar down the centre of each petal.
But don’t feel that you have to stick to these since there are many other first rate varieties of clematis in containers to grow!
Training to reduce height
But choice of variety isn’t the only way to keep your plant small. Really early bloomers such as Clematis alpina, macropetala and even the more compact varieties of montana can be trained around a support structure. Simply wind the long growth around the structure as they grow. Okay, so I admit that you are cheating and making it look as if those blooms are all the way up the stem but who cares if it works? The same can be said of many of the regular large flowered types but these are more inclined to flower on old and on newly grown shoots. This gives better spread of bloom.
I’ve simplified pruning of Clematis in my blog here.
Which varieties have you grown successfully in containers?
Which variety combinations of clematis in containers have worked best for you?