In spring, my favourite climbing plant is without question wisteria. The sight of the massed purple flower is breath taking and the scent of the blooms almost intoxicating. Yet this climber can be feared for its potential vigour, with many examples of old specimens that have not been maintained running rampant in gardens across Adelaide. It doesn’t need to be this way.
Varieties of Wisteria
There are a number of different varieties of these deciduous climbers available to home gardens, and while most people are more familiar with the common purple flowered forms seen adorning verandas and fences, and covering pergola, there are also white, pale pink varieties, some with extra long flowers up to 1m long, and even a double form. Being deciduous climbers they are perfect for situations where you want summer shade yet still have the winter sun shine through.
Recently I engaged the services of master Japanese gardener, Fumio Ueda and his son Shinya, to train the wisteria I had planted over the pergola on the western side of my home. These plants had been in for four years, yet only just taken off in the last twelve months. Fumio and his son have pruned and trained wisteria at my previous two gardens, and those of many of my clients, and I have seen the difference they make, with maximum flowers and minimum growth the result. I asked Fumio about his top tips when buying and planting wisteria and here they are:
What to buy?
When choosing which wisteria to buy, it’s all about the flowers! Have a clear vision of what you colour you like? Do I want a thick cluster of flowers? (commonly Chinese wisteria, Wisteria sinensis), or do I want a gentle cascade of petals under some foliage? (commonly Japanese wisteria, Wisteria floribunda). For the flower connoisseur, visit www.parrsnursery.com.au who is the main wholesale grower of wisterias in Australia and supplies the retail nurseries around SA. If you are buying at a nursery, ignore how many flower buds it has. Find a plant with the thickest, strongest looking trunk! How many to buy? If it’s purely for canopy you’ll only need one plant.
Where to plant them?
Wisteria loves full sun so if you are planting a new wisteria, make sure it gets full mid-day sun all year round. Avoid planting tall trees on the Northern side of the wisteria. If you have an existing wisteria, make sure to prune back any tree branches hanging directly above.
What care do they need?
Wisteria also loves water, especially during summer months (November to March). Their roots are shallow and wide-reaching like ‘Octopus tentacles’. They love stretching their roots under pavers, irrigated lawn, and thickly mulched garden beds. The key is to use your irrigation to encourage the roots to spread. If the only drippers you have are around the base of the trunk, connect more drippers to cover a larger area.
Encourage the strongest shoot to become the trunk. If you have more than one trunk, work towards reducing it down to one. The wisteria branches should ‘hug’ your pergola. This way, the flowers can cascade into view. Wisteria will naturally try to climb. If you are trying to cover the pergola, tie the branches down to get more coverage. The side shoots which grow off the branches should be cut short to create flowering spurs giving the appearance of a ‘water dragon’ (see Fumio’s drawing). If you have enough shade, cut all branches which shoot up above the canopy. The key to wisteria pruning is to be stubborn and merciless! And as far as when to prune? If you’ve had a go at pruning your roses in July, it’s time for you to get up on the ladder!