Wisteria formosa Issai is an outstanding, rampant climber with dense, lush, mid-green compound leaves that emerge as coppery-bronze in spring and turn yellow in autumn. It starts flowering at a younger age than other wisterias, bearing compact but plump, drooping clusters of pea-like, mauve to violet blooms flowers that have a central yellowy-green blotch and a slight fragrance. Dangling velvety green seedpods follow.
A new cross between a Japanese and Chinese wisteria, this is a large, extremely vigorous and fast-growing plant, ideal for rapid coverage of walls, pergolas, fences and trellises. It forms a massive plant and can become rampant if not controlled. Plant it in a sunny spot with a sturdy support and plenty of room for the roots to run. Prune regularly, and note that rich soil encourages leaf growth rather than flowers, so do not overfeed.
This plant requires some work, but is very rewarding if planted appropriately.
Also available trained as a half standard form, which can be kept in check easily and is a lovely way to see the show of blooms.
Common Names: Japanese Wisteria Issai
Pot Sizes: 10L (with two or three main stems) and 12L half standard
Hardiness: Hardy to –10°
Height and Spread: 12m x 8m, over 10–20 years
Preferred Soil Type: Any moist, well-drained soil
Aspect: South- or west-facing sheltered
Position: Full sun / Partial shade
Flowering Period: May – June
Care: Prune rigorously twice a year, towards the end of summer and mid-winter, to enhance flowering and keep it restrained. Check for runners than may invade eaves and could eventually cause structural damage.
*Please note this plant is harmful if eaten*