This store requires javascript to be enabled for some features to work correctly.
Family: Fabaceae · Pot diameter: 15 cm
Wisteria ‘Black Dragon’ brings to a pergola the deepest, most ink-like violet one could expect from a single-flowered Japanese wisteria. Its hanging racemes open gradually among young bronze-tinted leaves, creating an almost velvety contrast. The fragrance is light and refined, while the dark colour keeps the composition elegant even at peak bloom. It is theatrical without ever becoming loud.
In current taxonomic use, the plain trade name ‘Black Dragon’ corresponds to Wisteria floribunda ‘Kokuryū’. Its clockwise-twining stems can be trained beautifully over an entrance or seating area, where the longer racemes remain visible from below and the old wood retains a sculptural presence after autumn leaf fall.
The single-flowered Wisteria floribunda ‘Kokuryū’, the exact current match for ‘Black Dragon’, has held the RHS Recommended: Award of Garden Merit since 2012.
Its identity rests on exceptionally dark single flowers, the gradual progression of bloom down each raceme and the seasonal contrast of bronze, green and golden-yellow foliage.
The violet-purple flowers are considered among the deepest coloured single-flowered selections of Wisteria floribunda. Their colour appears inkier at the centre and brightens towards the standard petal.
The hanging racemes can reach about 50 cm and open in sequence from the upper base towards the lower tip, so open flowers and buds remain present together.
Bronze new growth frames the dark flowers, mature foliage turns green, and autumn brings golden-yellow tones before the woody trunk is revealed.
Why you will love it: it delivers genuinely dark, single violet flowers on long racemes, framed by a subtle progression of bronze, green and gold.
Place it on a pergola or arch with a pale beam, or against a south- or west-facing wall with strong wires. Its mature supported scale reaches 8–12 m in height and more than 8 m in spread, so keep the trunk away from gutters and leave a clear zone beneath the beams for racemes up to 50 cm long. A lower viewing angle reveals the colour most effectively.
Pair the almost ink-black violet with amber, cream and yellow-green tones. Keep lower plants in the outer root zone, where they can make use of the shifting shade created by the pergola.
Full sun for deep colour and generous flowering; light shade is tolerated, usually with fewer racemes.
Water deeply when the surface begins to dry, maintaining even moisture during establishment and intense summer heat.
RHS H6. Spring new growth and the racemes perform best in a sheltered position away from late frost and drying winds.
Harmful if eaten by people or animals; pods and seeds require particular care. Wear gloves when pruning.
Build the pergola from metal or heavy timber before planting. The woody trunk thickens considerably and can distort slender trelliswork; inspect the soft ties during every growing season.
Allow young shoots to follow the natural clockwise twining of Wisteria floribunda. Guide one main trunk and distribute the principal framework branches along the beam without twisting them in the opposite direction.
Choose deep, fertile, well-drained soil and a position with direct sun. Protect the plant from strong winds that buffet the long racemes and from sites where winter water collects.
Plant at the same depth as in the current 15 cm pot and water well. For long-term cultivation out of the ground, move it gradually into a heavy pot at least 45 cm across, with a separate substantial support.
Do not let the root zone dry deeply during establishment. Later, water slowly and thoroughly during prolonged drought, allowing the surface to aerate between waterings.
A layer of mature compost in spring usually meets its needs. Excess nitrogen promotes long leafy shoots and can delay the formation of flowering spurs.
In July or August, shorten the long new side shoots to 5–6 leaves. Leave the permanent framework intact and remove only growth that tangles or heads towards gutters.
In January or February, cut those same side shoots back to 2–3 buds. The bare wood makes it easier to distinguish short flowering positions from long leaders.
At first, the root system and one clear main shoot take priority. Guide it up the post without tight ties and remove competing shoots gradually.
Once it reaches the top, spread two or three framework branches to different lengths. Controlled asymmetry leaves open spaces where the racemes can hang clearly.
At its mature scale of 8–12 m by more than 8 m, racemes up to 50 cm long unfold in sequence beneath the beam while the foliage forms a summer ceiling.
A vigorous Japanese wisteria on a permanent pergola, flowering with the young foliage and carrying dark single racemes up to 50 cm long that need clear space below.
Bronze spring growth turns into green summer shade, yellows in autumn and leaves the clockwise-twining woody framework exposed in winter.
What to expect after planting: the deep colour is not a sign of instant maturity. A young plant invests first in roots and extension; with light, time and a disciplined framework, the single racemes become increasingly clear beneath the beam.
‘Kokuryū’ is recorded as a Japanese horticultural selection of Wisteria floribunda. Its name was rendered in the West as ‘Black Dragon’ and linked to the exceptionally deep violet of its single flowers, but the historical record remains fragmentary: no named selector, parents or secure date of creation has been preserved.
Over time the same selection also circulated as ‘Royal Purple’, ‘Russelliana’ and ‘Violacea’. The RHS now accepts Wisteria floribunda ‘Kokuryū’ as the principal name and lists the plain ‘Black Dragon’ among its synonyms, separately from the cultivar ‘Yae-kokuryū’.
The exact single-flowered Wisteria floribunda ‘Kokuryū’ has held the RHS Recommended: Award of Garden Merit since 2012.
Each single flower has one large standard petal, two wings and two petals forming a keel around the reproductive organs. This papilionaceous structure is the defining feature of ‘Kokuryū’.
Flowering is acropetal: it starts at the base of the inflorescence, high near its point of attachment, and progresses towards the lower tip. The largest open flowers therefore sit above the younger buds.
In thicker stems of Wisteria floribunda, cells in the cortical parenchyma can resume division and form ectopic cambia. These additional vascular layers are linked with KNOX genes and help the liana combine flexibility with striking secondary thickening.
What you need to know about the precise single-flowered identity, dark colour, twining direction and training of ‘Black Dragon’.
The plain ‘Black Dragon’ is currently matched to Wisteria floribunda ‘Kokuryū’. ‘Royal Purple’, ‘Russelliana’ and ‘Violacea’ are recorded as synonyms of the same single-flowered selection.
They are single, violet-purple and among the darkest single-flowered Japanese wisterias. The fragrance is light and the hanging racemes can reach about 50 cm.
No. Flowering progresses gradually from the upper base of the raceme towards the lower tip. For several days, open flowers remain higher while younger buds sit below.
As Wisteria floribunda, it develops clockwise-twining shoots. Let them follow their natural direction and use soft ties only for initial guidance.
Youth, shade, excess nitrogen or removal of the short flowering spurs can delay the display. It needs a mature woody framework, sun and consistent twice-yearly pruning.
Only where there is no risk of chewing or ingestion. All parts are considered harmful, especially pods and seeds. Collect fallen material and wear gloves when working with the plant.
