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Spectacular wisteria in flower for first time after round-the-clock watch

Following a 24-hour vigil by Wisley’s horticulturists, the Wisteria Walk’s magnificent purple cultivar is blooming for the first time

After a five-year wait, a magnificent scented wisteria has burst into bloom at RHS Garden Wisley in Surrey.

The Wisteria Walk, planted in 2018, has already proved a spectacle with its white-flowered Wisteria ‘Kimono’. However, the beautiful purple

cultivar ‘Kokuryu’ has always been stopped in its tracks by late frosts, which have damaged the flower buds.

This year, with fewer frosts predicted, the team went to extraordinary lengths to nudge this tender beauty into bloom by keeping night vigils with warming fires to keep the cold at bay.
 
Now, for the very first time and thanks to the dedication of the horticultural team, this is the spring when we can finally enjoy the breath-taking two-tone display in all its glory.

When can I see it?

‘Kokuryu’ began blooming on the Wisteria Walk in early May, reaching its peak around mid-May. Within a couple of weeks it was joined by the white ‘Kimono’, which takes the display through to the end of May.

Pushing boundaries

In 2018, two special cultivars were selected to adorn the wisteria arch, inspired by a visit to the national collection in Kent. Curator Matt Pottage and his team were in search of outstanding scent, rich, two-tone colour and luxuriously long racemes of flowers, which would hang down into the walkway to provide a wonderfully sensory experience.

The chosen candidates were a stunning blue-tinged white variety called ‘Kimono’ and an opulent purple variety called ‘Kokuryu’. Mingling together on the arch, these would create a spectacular bicolour effect, with their staggered blooming times extending the season of interest. 

‘Kokuryu’ is amazing for its scent and it’s a really rich, beautiful purple, so we were very keen to plant it

- Matt Pottage, Curator

While the dormant plant can withstand cold winters, ‘Kokuryu’ is a particularly early-flowering cultivar whose buds can be damaged by late spring frosts. However, with outstanding floral qualities and a trend towards a warmer future at Wisley, this was a risk worth taking. 

We’ve been unlucky for five years; maybe for the next five we’ll be lucky. We are trying it, and it’s still early days in terms of the long future of the plants


The pale-flowered cultivar ‘Kimono’ in bloom on the Wisteria Walk in 2022

Saving the blooms

A run of late frosts over the last few years meant that ‘Kokuryu’ had not previously bloomed on the Wisteria Walk; the limelight dominated by the pale ‘Kimono’. However, for the very first time and thanks to true dedication from the horticultural team, this is the spring when we can finally enjoy the breathtaking two-tone display in all its glory.

Wisteria loved the heat last summer – it’s really promoted good wood ripening and flower bud set, so when we saw the volume of buds coming, we thought wow, this could be amazing

By early April, the elusive ‘Kokuryu’ was covered in buds and with only a few frosty nights standing between them and an incandescent display, Matt and his team decided to pull out all the stops to protect the blooms. 

Traditionally, when orchards and vineyards need to be protected from late frosts, sprinklers are left running overnight to constantly douse the buds in running water, or paraffin-based vineyard candles are lit. Uncomfortable with the environmental costs of these traditional methods, or with using any intervention for more than a couple of exceptional nights, Matt and his team decided, for two nights only, to improvise.

Surplus wood produced from tree surgery around the garden was gathered, and nine fire pits laid out along the length of the Wisteria Walk. Come nightfall, these were lit and dedicated horticulturists stayed in attendance throughout the night, taking shifts to stoke the flames.

We had no idea if it was actually going to work

- Matt Pottage, Curator

The morning after the second frosty night, the team gingerly inspected the buds. Within about 5-6 hours, frost-damaged buds start to lose their pressure and go limp. But these buds appeared in fine fettle, and by a couple of days later, it was clear to see that they had survived unscathed and were continuing to grow.
 

What can we expect to see?

By April the whole arch was bursting with buds, ripe with promise for 2-3 weeks of really amazing display. By mid-May the wisteria was in full bloom, providing not just a stunning visual spectacle, but also a giddy perfume which is unmissable.

This isn’t an everyday thing – it’s an unusual spectacle

“The idea with the design is that the purple is early into flower, so the purple kicks off, the whole things lights up purple, and then the white follows after, and it finishes on white. At that crossover point, which we’ve never seen but will hopefully see this year, we have a crossover of purple and white, giving a two-tone effect,” says Matt.

‘Kokuryu’ burst into bloom in early May, and within a couple of weeks was joined by the paler ‘Kimono’, which takes the display through to the end of May.

In addition to ‘Kokuryu’ and ‘Kimono’, 16 other wisteria cultivars have been between the topiary alongside the Walk, providing a diverse display in a range of pinks, purples, blues and whites.
 

Planting for the future

Wisley is known for its magnificent collection of wisterias, expected to burst into glorious bloom all over the garden in April and May. The tree-climbing wisterias scaling 80ft-tall oaks in the Oakwood are thought to be unique in the UK, while compact freestanding standards showcase how wisterias can be grown even in a small open space.

To add another immersive dimension to the collection, Wisley’s Wisteria Walk was created in 2018. At 75m long, it’s an impressive spectacle, and one of very few like it in the UK. 

Planting a wisteria is a long-term investment. As Wisley’s Garden Manager Peter Jones puts it, “you plant wisterias for 100 years”. It is hoped that the Wisteria Walk will be a landscape feature that lasts well into the future, and it is hoped that ‘Kokuryu’ is a cultivar that will only become more successful in a warming climate.

Wisteria can easily live for 100 years, and are doing better and better in the heat. This is a plant for the future

Wisteria is also a valuably climate-resilient plant. During last summer’s extreme heat and drought, Wisley’s wisterias suffered no drought stress at all. In fact, the heat promoted unusually good wood ripening and bud formation, leading to an expected abundance of flower this spring.

‘Kokuryu’ in bloom for the first time on the Wisteria Walk in mid-May 2023, intermingled with the paler ‘Kimono’
As more and more gardeners reconsider what they can grow that will thrive in a changing climate, wisteria surely deserves a place on the list. Visit Wisley this late April or early May to see the Wisteria Walk as never before, and gather all the inspiration you need to choose your perfect cultivar from the huge range on display around the garden.

Wisley has always been an experimental garden, which gives us a freedom to try things such as ‘Kokuryu’. It’s from the experimentation that you learn

- Matt Pottage, Curator

 
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