Gardens

How to grow wisteria – and the best time to plant this firm favorite

At its glorious peak in late spring and early summer, wisteria is one of the most spellbinding plants you can grow, but patience and (a ton of) pruning is required

How to grow wisteria
(Image credit: Getty Images)

Discovering how to grow wisteria in your backyard will be one of the most rewarding gardening chores you ever take on. 

Wisteria is the unrivalled queen of climbers, with its long racemes of flowers, born to dangle from a wall or hang through a pergola, filling the air with scent. But a queen can rule with an iron fist. There aren’t many plants that look more romantic and feminine, but don’t be fooled by the cascade of softness: wisterias will swallow your house whole, if you let them. 

Wisteria stems grow at speed and, once thick and woody, will strangle tree trunks and bend lead pipes. Because some species have become invasive in part of the US, it’s important to learn about these very beautiful plants and what is required to contain their vigor before planting one. 

Treated with care, wisteria are one of the best climbing plants you can grow – a delight for decades, producing a jaw-dropping curtain of flower racemes in May and June. These hanging tails of pea-like blooms clothe the front of the house, like a thousand flower garlands, and send their delicious perfume through open windows, making every spring magical. 

How to grow wisteria

How to grow wisteria

(Image credit: Getty Images)

Before we begin the practical instructions on how to grow wisteria, let's talk which wisteria to plant.

Always purchase wisterias that are grafted (grown on rootstock) and come from a reputable supplier. There are white, pink, mauve, blue, and purple cultivars; some are strongly scented, while others only have a light fragrance. They vary in their vigor and in the length of their racemes. 

Forms of Chinese wisteria (W. sinensis) and silky wisteria (W. brachybotrys) are suitable for walls and houses; whereas the Japanese wisteria (W. floribunda) is better as pergola ideas, where its very long racemes will not be covered by foliage. 

Of the Japanese forms, ’Yae-kokuryu’ is a traditional purple variety; ‘Shiro-noda’ is an elegant white; the pink ‘Hon-beni’ would be at home in an English cottage garden; and the very long (up to 4ft/1.2m) racemes of ‘Kyushaku’ are white and violet. 

If you live in one of the US states where W. sinensis or W. floribunda have become invasive (such as Virginia or North Carolina), it’s not advised to grow them or their more vigorous cultivars, unless you are prepared to keep them in careful check with pruning. 

Instead, grow one of the less aggressive cultivars, such as the beautiful white ‘Jako’, or opt for an American wisteria, such as W. frutescens ’Amethyst Falls’, which won’t strangle forests if it escapes from your garden. Other relatively compact options include W. frutescens var. macrostachya ‘Blue Moon’ and ‘Aunt Dee’, which both smell of sweet peas. 

Thankfully, in many parts of the US and in the UK, wisteria is not an invading pest and easy to manage. 

When to plant wisteria

Plant between October and April, on a day when the ground is not frozen or waterlogged. 

Where to plant wisteria

It's best to grow wisteria in a sheltered site in full sun, such as a south or west-facing facade. The soil must be fertile and well-drained, so dig in plenty of organic matter (such as compost) upon planting.  

If growing wisteria up a wall or the front of a house, take the time to erect a sturdy frame for the wisteria to climb – potentially, over many decades. Wooden trellis can rot, so a tensioning system of wires is arguably better. The wires must tighten themselves as the plant puts on weight or be easy for you to tighten (via turnbuckles, for instance).

How to plant wisteria

CLEMATIS MONTANA 'RUBENS' with wisteria

(Image credit: Getty Images)

To grow wisteria successfully, it must be started off well. This is how.

1. Soak the wisteria

Soak the wisteria for an hour before planting by sitting the base of the pot in water. 

2. Dig a hole of the correct size

While the wisteria is soaking, dig a hole at least 3ft (90cm) away from the wall it is going to climb. The hole ought to be 2-3 times wider than the wisteria’s container. 

3. Loosen the soil, add compost

Loosen the soil at the bottom of the hole well with a fork, and dig in organic matter, such as compost. 

4. Position the wisteria

Check the position of the graft (the bulbous union between the roots and the main stem) is above the ground. 

5. Plant the wisteria

Backfill with soil, and firm in to prevent air pockets. Then, water in. 

How to control a wisteria

Staring up at a mature wisteria in full bloom, it resembles a purple waterfall flowing over the front of the house. These plants are beautiful, mighty beasts that require twice yearly pruning to keep them in check. It’s worth going to see a sizeable old wisteria – such as those in Sierra Madre, California and Knole in Kent, England – both for the delight of seeing them, but also to realise their vigor. 

The pruning is easy, but must be done twice a year. The first cut should be done in July or August by removing excess whippy growth; to around 12in (30cm) and 5 or 6 leaves. Then, in February, take these shoots back to 2 or 3 buds (around 4in/10cm). Pruning wisteria will encourage a good show of flowers, but also keep the ambitious wisteria out of your guttering and away from your roof tiles. 

Allow a new, young wisteria to climb to the top of the structure or wall you intend it to flower upon. Then begin to prune and tie in strong side stems horizontally, which will eventually create a whole wall of flowers, rather than just a mass of flowers at the top. It’s best to tie with flexible tubing ties that stretch as the plant grows, and to repeatedly untie and retie stems to prevent them becoming attached to the wires. 

Why isn't my wisteria flowering?

A baby wisteria may not flower for a few years after planting. To care for young wisteria plants and to ensure flowering, water them regularly and generously during their first two seasons, especially in drought or if the ground where they are planted is dry. Feed every spring with a general-purpose fertiliser until established, but never over-feed. 

How fast does wisteria grow?

While wisteria take time to flower for the first time, they are quick to grow – up to 10 feet or more a year. This makes them a wonderful choice when you are looking for garden privacy ideas or garden shade ideas, as they will be in full leaf throughout the summer months. However, it also means that you have to be vigilant about pruning if you don't want them to take over.