Compound leaves up to 8 inches long, each with 7 to 17 deep green leaflets that are matt grey underneath, give the Japanese pagoda tree (Styphnolobium japonicum) its airy canopy. Best known as a majestic standalone for large gardens and parks, it asks for deep, non-chalky soil and full sun, repaying with hanging clusters of whitish yellow flowers once mature.
| Botanical name | Styphnolobium japonicum, formerly Sophora |
|---|---|
| Common Name | Japanese pagoda tree |
| Family | Fabaceae |
| Type | slow-growing tree |
| Height | 60 feet (20 meters) |
| Breadth | 45 to 60 feet (15 to 20 m) |
| Exposure | sun to shade |
| Soil | deep, not chalky |
| Hardiness | hardy |
| Foliage | deciduous |
| Flowering | end of summer for older specimens |
Native to Asia, the pagoda tree mostly stands out thanks to its large, airy leafage. Leaves can reach 8 inches long (20cm) and are composite leaves: each has 7 to 17 deep green oval leaflets that are a mat gray color underneath. The summer blooming is not a stunner at all – it’s kind of hidden by all the leaves. Moreover, only older, mature specimens actually bear flowers. Whitish yellow in color, the flowers are gathered into hanging clusters.
The elegant Sophora japonica also exists in a weeping form (S. japonica ‘Pendula’). This cultivar is much smaller. It has a particularly appealing bearing that completely transforms the appearance of the garden. Branches hang over, creating an intimate hiding place underneath. In winter, the leaves fall and the lovely umbrella-like branches are revealed.
Beyond the plain species and the weeping ‘Pendula’, nurseries offer selections that differ mainly in habit and eventual size. Pick according to the room you have and the shape you want.
| Variety | Habit | Mature size | Why choose it |
|---|---|---|---|
| ‘Pendula’ | Weeping, umbrella-like | Small, around 10–15 ft | Creates a sheltered space beneath; rarely flowers |
| ‘Regent’ | Broad, rounded crown | Large, 40–50 ft | Faster growing and flowers at a younger age |
| ‘Fastigiata’ | Narrowly columnar | Tall, narrow | Fits avenues and tight garden corners |
Once mature enough to bloom, Japanese pagoda trees such as ‘Regent’ drop spent flowers and long beaded seed pods, so site them well away from paving, pools and parking spaces.
Carpinus betulus ‘Fastigiata’ is narrowly upright when young but broadens into a wide oval or vase shape with age, so allow considerably more width than the young nursery plant suggests.
A major advantage of Sophora japonica is that it doesn’t have very stringent requirements to grow. Though it can adapt to nearly any growing environment, you’ll have the best results with deep soil – the less chalky, the better – and lots of warmth and full sun.
As for most trees and shrubs, success is most guaranteed when planting Sophora japonica in Fall. This makes settling in easier. However, thanks to its adaptivity, it’s possible to set it up in Spring.
Over the first year, help young specimens grow by topdressing the soil around the base. Just spread a little soil mix or mature compost around the tree at the beginning of Spring. It might be necessary to perform structural pruning in years 2 and 3, to guide your Sophora japonica. Afterwards, all that’s needed is to eliminate old wood and branches that are too low.
Multiply your pagoda tree by sowing its seeds in pots, in a cold frame. Before planting, soak them for a few hours in a glass of water.
A naturally resistant tree, Styphnolobium japonica isn’t very vulnerable to either pests nor diseases.
A majestic tree, S. japonica will look nicest in large gardens and parks. Since it grows rather large, it’s usually planted as a standalone, eventually surrounded by a flower bed once it gets a bit taller. It immediately brings to mind visions of beautiful Japanese gardens.
The Japanese pagoda tree (Styphnolobium japonicum) bears creamy flower clusters in late summer, when few other temperate trees are blooming, making it a valued nectar source for honeybees and other pollinators.
The pagoda tree tolerates heat, air pollution and compacted ground, which is why it has long been used to line city streets and courtyards.
