Wisteria is a purely elegant climber, an English cottage garden classic which produces a stunning display of scented blooms in the spring.
It is by far the most popular climbing plant with my customers, but some are a little apprehensive about the training and pruning involved with a wisteria.
When really they are a much easier plant to maintain than people think. With the right amount of care, a wisteria will reward you and give you pleasure in your garden year-after-year.
Where To Plant Wisteria
When planting a wisteria in your garden, the location of where it is going to flourish is one of the most important things to factor in.
Wisteria is a twining climber, so they need to be grown on wires, set vertically or in a fan shape on a wall.
They are also ideal for growing or a sturdy pergola or through established trees in the garden too.
Wisteria requires pruning twice a year to help promote flowering, so easy access to the plant is vital when choosing the location for your wisteria.
Wisteria’s like a sunny position, favouring a south or west aspect. They need plenty of rays from the sun to ripen the wood to help produce bigger blooms.
Wisteria will grow in partial shade but will probably never flower, so sunshine is essential.
They will grow in any type of soil, but the soil needs to be moist and free draining.
Your wisteria is long-lived, so it is a good idea to prepare the soil before planting by adding some garden compost or well-rotted manure to improve the drainage and fertility of the soil.
Choosing Your Wisteria
For many years it was the common Chinese wisteria (W. sinensis) that only existed in our gardens here in the UK. Today there is an array of cultivars for you to choose from.
I believe another reason why gardeners are a bit wary of planting a wisteria in their garden is that they think that it is going to be too invasive and take over their whole house.
True the Chinese wisteria is an invasive plant and can grow up to 40ft (12m) with a 25ft (8m) spread. But this is another reason for regular pruning so that you can keep it in check.
Today’s newer cultivars are less invasive and are mainly of Japanese origin, which have strange names, and in some cases strange flower formations and colours.
The most popular wisteria I sell is Amethyst Falls, a relatively new variety to the UK and is native to North American. It flowers at the start of spring and then again in late summer.
Where many varieties of wisterias can take up to five years to flower, Amethyst Falls will flower in its first year.
In its early years, it will remain compact and manageable and as such makes it brilliant for growing in a large patio pot.
It will eventually reach a height of 15ft (5m), with spread to around 6ft (2m) if left un-pruned. But if maintained at half this size it will still yield masses of flowers every single spring and summer.
When buying a wisteria check the plant has been grafted and not grown from seed, as plants grown from seed can take up to 20 years to flower.
The vast majority of the wisterias I sell are either in bud or are in the very early stages of flowering.
When To Prune Wisteria
To get the best flower display from your wisteria it’s worth taking the time and effort to prune it twice a year.
Wisteria should be pruned in July or August and then again in late winter around January/February time.
How To Prune Wisteria
The purpose of the summer prune is to cut the new whippy growth back to the structure of the plant.
This will create air flow around the plant and allow sunlight to ripen the wood to produce the flower display you desire from your wisteria.
When cutting the new whippy growth back, you need to cut the stem back to 5 buds.
The first task of the winter prune should be to cut out any dead, diseased and crossing branches that have developed over the winter.
Any whispy stems can also cut back to tidy up your plant.
The long shoots that were cut back in the previous summer now need to be reduced to 2 buds.
This process produces spurs which allow the fatter flower buds to remain to produce larger flowers.
The difference between the buds on your wisteria should be quite easy to distinguish. The big fat buds produce flowers and the longer thinner buds produce the foliage on a wisteria.
If you forgot to prune your wisteria in the previous summer don’t stress too much as you can cut the shoots back 2 buds now, and you still have an amazing looking wisteria in a few months time.
When Does Wisteria Bloom?
Wisteria typically blooms in May and June in the UK, for around 3-4 weeks.
If you prune away flower heads as soon as they wilt or droop, this may lead to a second flourish of flowers later in the summer.
Why Is My Wisteria Not Blooming?
As mentioned before some varieties of can take up to 5 years to flower, and if grown from seed it can 20 years.
Choosing a named cultivar should provide more flowering success. Don’t be alarmed though if such a plant is reluctant to flower in the first year or two after planting. This is perfectly normal and the plant will settle back into flowering once the roots are established.
Like many spring flowering plants, wisterias start to develop in the late summer of the previous year.
Dry soil occurring between July and September can cause the flower buds to abort. Ensure your wisteria has an adequate supply of water during this period.
A cold snap in spring can also cause flower buds to drop before opening.
Does Wisteria Bloom On New Growth?
Wisteria produces its flowers on the previous year’s growth.
Does Wisteria Lose Its Leaves
Wisterias are a deciduous climber and will lose its leaves in the autumn.
Why Is My Wisteria Going Yellow?
The most common reason for your wisteria’s leaves turning yellow is an iron deficiency in the soil.
Another reason possible issue is poor drainage. Boggy and soggy soil is not a condition that a wisteria like to live in. Excess moisture will result in limp, yellowing leaves that will start to fall off your plant.
Why Is My Wisteria Wilting?
All of these problems below prevent adequate water uptake through the roots, leading to wilting and die-back.
- Wisteria can suffer from root diseases such as honey fungus and Phytophthora root rot.
- Waterlogging can also cause root decay, in both soil and container-grown plants.
- Roots of container plants, in particular, can suffer damage from vine weevil grubs.
Wisteria is also prone to graft failure after many years of satisfactory growth, this happens when the graft union often decays.
A clue to graft failure is the production of new shoots from below ground level, while the top part has died back, these are being produced by the rootstock.
What Feed Do You Give Wisteria?
Feeding your wisteria with a rose fertiliser every March will help to promote healthy growth and regular flowering.