Chinese wisteria

Chinese wisteria: how do you recognise it?

Habit

Vigorous, woody twining climber up to 15–20 m, with thick, sinuous stems; can also be grown as a free-standing standard.

Leaf

Alternate, odd-pinnate with 7–13 leaflets.

Stems

Thick, woody stems that twist around supports.

Flower

Hanging racemes of 15–30 cm, bluish-purple and fragrant, in May, before or with the leaves.

Fruit

Velvety pods; the seeds are poisonous.

Difference from Japanese wisteria

Japanese wisteria has even longer racemes and twines the other way.

Flowering: April–May · Pruning: January–February and July–August

Identify by feature: Purple or blue flowers · Hanging flower clusters · Pods · Twining climbers

Looks like it, but isn’t

• Japanese wisteria (Wisteria floribunda): even longer racemes; twines the other way.

Why grow it?

• One of the most spectacular flowering plants in the garden, with racemes of 15–30 cm.
• Fragrant flowers in May, busy with bumblebees and bees.
• Provides shade over a pergola in summer.
• Can live to a great age and develop an impressive, gnarled trunk.

Chinese wisteria: where does it grow best?

• Full sun: in shade it hardly flowers.
• Any well-drained soil that isn’t too wet.
• It twines around its support and needs a very sturdy pergola, heavy-gauge wires or a wall trellis on spacers; light structures give way after a few years.
• Keep it away from downpipes, gutters, shutters and trees: it can strangle them.

Light

Full sun

Legal basis

Any garden soil

Moisture

Normal

Size

15 m tall, 5 m wide

Hardiness

Throughout Belgium, no protection needed

Goes well with

• Common lilac: Flowers at the same time in May, with a similar colour and scent.
• English lavender: Flowers in summer at the sunny foot of the pergola, once the wisteria has finished.
• Rosemary: An evergreen, fragrant shrublet for the same warm, sunny spot.

Good and bad companions

Best kept away from

• Twines around young trees and shrubs and can strangle them: hawthorn, goat willow, japanese cherry, judas tree, chusan palm, olive tree

Chinese wisteria: when and how to plant it?

1. Plant in autumn or spring, from a pot.
2. Buy a grafted or cutting-raised plant that is already flowering: seedlings sometimes take 10–20 years to flower.
3. Plant 30–50 cm from the wall or post and guide the shoots to the support.
4. From the start, choose one or a few main stems and tie the side branches in horizontally: that is where the flower racemes will come later.

Care

Watering

In dry spells during the first year, and in late summer, when it forms next year’s flower buds.

Feeding

Sparingly: too much nitrogen gives lots of leaves and few flowers.

Tying in

Tie young stems in loosely and check every year that they are not growing into the wires or ties.

Runners

It sends out long runners over the ground: cut them off before they root.

Tip: No room for a pergola? Grow wisteria as a free-standing standard on a sturdy post: with the same pruning it flowers just as profusely.

Chinese wisteria: when to prune it?

Pruning months: January–February and July–August.

When: Twice a year: in July–August and in January–February.

How:

• In summer, cut the long new shoots back to 5–6 leaves; in winter, shorten them further to 2–3 buds. This gives you plenty of flower clusters.
• In summer, also remove shoots heading for gutters, windows or the roof.
• In winter, spare the fat, round buds: those are flower buds; the slim, pointed ones are leaf buds.

Caution: Don’t leave long shoots unpruned: within a few years they become thick stems that twist gutters and shutters.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Layering

In spring, lay a long, pliable shoot on the ground and cover a section with soil; after a year you can cut it free.

Sowing

Possible, but a seedling only flowers after many years and often less well: better to buy a grafted plant.

Chinese wisteria: how does it get through the winter?

Hardy throughout Belgium: no protection needed.

• Hardy; the flower buds can, however, be frosted by night frost in April.
• In winter you see the framework best: the ideal time to check the support and tie in the stems.

Diseases and pests

• No flowers: Usually a seedling, too much shade, too much fertiliser or too little pruning. Prune twice a year and give no nitrogen.
• Bud drop: The flower buds drop before they open, due to drought or night frost in spring. Water in dry spells.
• Strangling: Stems in downpipes, gutters or around young trees. Cut them away in time; a thick stem can no longer be removed without damage.

Through the year

• January: Winter pruning: shorten side shoots to 2–3 buds.
• February: Finish winter pruning; check the support and wires.
• April: Buds swell: cover in night frost where possible.
• May: Flowering: long, fragrant racemes.
• June: Remove spent racemes and pods; cut off runners.
• July: Summer pruning: long shoots back to 5–6 leaves.
• August: Summer pruning; water in dry spells.
• October: Planting.

What can you use it for?

Garden and landscape

Spectacular flowering climber for a sturdy pergola or house wall.

For wildlife

Bumblebees and bees flock to the flower clusters.

Caution: Seeds and pods are poisonous. The stems grow so strong they can strangle gutters and young trees.

Good for wildlife

Bumblebees

Nectar and pollen for bumblebees, also from deep flowers and early in spring.

Bees

Nectar and pollen for honeybees and wild bees.

Did you know?

• The stems grow so strong that they can twist downpipes, gutters and even balconies.
• The name Wisteria honours the American physician Caspar Wistar.
• An exotic from China that does not spread in the wild here; a wisteria can live for more than a hundred years.
• The genus Wisteria was named by the botanist Thomas Nuttall after the American physician and anatomist Caspar Wistar.
• As a member of the pea family, wisteria lives with bacteria in root nodules that fix nitrogen from the air; extra nitrogen fertiliser mainly produces lots of leaves.