We are literally climbing the walls! Apparently, climbers in France are increasing in popularity by leaps and bounds.
The statistics people who occupy their time with such interesting reflections believe that this is because we are all gardening in increasingly small spaces and our imaginations are blossoming as we run out of room.
Enter pots and containers: even those of you who garden on balconies probably have room for at least one container-grown climber.
Forget the prickly ‘queen’ of climbers, the rose, and turn instead to the much lighter, balcony-friendly framework of clematis.
Three groups for pruning
You may remember that clematis are divided into three groups, based on pruning regime.
Group 1 (the spring-flowering sort, such as montana, alpina and macropetala) requires no pruning, or at least only to keep them within bounds.
Group 3 gets a hard haircut to about 50cm above soil level in spring, consequently they were always my first recommendation as container plants. Providing they are fed and watered well through the season, your display will be consistent over years.
Group 2, the large-flowered clematis (think of ‘Nelly Moser’), I’d have been disinclined to recommend for pot cultivation in the past, since they are strong-growing, but require a more complicated annual pruning regime, cutting away a volume of old growth to encourage new, while still retaining a good flowering framework.
Enter modern breeders who, following our changing habits, have concentrated on that group to produce plants perfect for pot-work - and compact enough at an average of 2.5metres to need little or no pruning!
Where to plant them?
Clematis are not ‘a doddle’ – you have to focus on pleasing them by keeping ‘head in the sun, feet in the shade’.
Think of our native European ‘Old Man’s Beard’, Clematis vitalba, and visualise the way it seeds itself at the base of a hedge or large shrub, then hauls its way by means of twining stems to the top.
So, make sure you provide shade at the roots.
The position of the plant could help, but you can also plant small-leaved ivies or herbaceous plants like heuchera to shade the roots.
Personally, since pot-grown clematis really need to be top-dressed annually (scraping away the top layer of compost in spring and adding fresh, mixed with slow-release fertiliser), I’m inclined to use bedding plants instead of perennials.
Choose the right container
Get your container right – no smaller than 18cm diameter and definitely not plastic, since the roots will heat up too much in the summer.
Then make sure you have the climbing structure in place before you plant: a purpose-made tripod or obelisk, trellising on a wall (or, with modern containers, integral to the unit), even pea netting if you want the clematis to climb a post.
When planting, the collar of the plant should go about 5cm below soil level.
This is crucial for Group 2 types, since these are much more prone to ‘wilt’ than the other groups.
Wilt is a fungal disease that enters the sap of the plant if the stems are damaged, but a strong root system and collar below soil level increases the chances of a plant reshooting from the buried collar.
Feeding and watering
Clematis are greedy feeders and, particularly in a pot, will need to be top-dressed each spring, fed regularly and watered every few days during the season, depending on the weather. If you use a ‘soucoupe’ below your pot, make sure it is never allowed to remain full of water.
Excess water at the root spells death.
Choose a variety
So – what to choose? As I’ve said, In the past I’ve gone for C. viticella or C. jackmanii from Group 3, due to their ease of pruning, but the less vigorous spring-flowering Group 1 types, such as C. alpina, C. macropetala and C. cirrhosa (for warmer regions) are also worth a whirl.
A newcomer to the market, now available in France, looks just peachy – C. ‘Amber’ (from C. koreana) is recommended for pot-growing and is an unusual shade of pale yellow, tinged pink on the reverse of the petals.
Raymond Evison is ‘king’ of British clematis and his ‘Boulevard’ series was bred specially for container growing: I’ve found at least one in France, light blue ‘Boulevard Cezanne’.
But we don’t really need to look further than our own shores, since we are blessed with two specialist nurseries, both exhibiting at all the major French horticultural shows: Pépinières Travers and Javoy Plantes.
Both host national collections of clematis (CCVS): Travers at L’ Arboretum des Prés des Culands (Meung-sur-Loire) and Javoy in the Jardin des Plantes at Orléans and the Domaine Albizia in Normandy.
In 2021, Javoy hosted ‘portes ouvertes’ days in September, which would be fascinating, since they propagate all their own plants, grow the plants on in the open ground and irrigate, feed and water only in an environmentally sustainable manner – recycled irrigation systems, integrated pest management, the lot!
Both nurseries recommend plants for container culture.
Travers were responsible for the ‘Success’ range, bred specially for pots in a range of colours.
They sell their plants online through their partner, www.clematite.net.
Javoy’s website recommends a rather appealing container duo, of which both partners were bred by the nursery: summer-flowering Clematis viticella ‘Burning Love’ with winter/spring-flowering C. cirrhosa ‘Christmas Surprise’.
You can find a list of garden centres supplying their plants on their site (www.javoy-plantes.com).