Styphnolobium japonicum is a large, rounded, shade tree that doubles as an ornamental tree, profusely flowering in Aug. or early Sept. with creamy-yellow large inflorescences. Japanese Pagodatree has many liabilities that limit the planting of this unusual tree in urban landscapes. Former scientific name: Sophora japonica
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F E A T U R E S |
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Form
-large shade tree, doubling as a large ornamental tree
maturing at about 60' tall x 80' wide, but can get even larger
-upright rounded growth habit in youth, becoming more spreading with age
rapid growth rate in youth and middle age, becoming a medium growth rate with maturity |
Foliage
-alternate, medium to dark green, with about 9-13 ovate leaflets (with acute apices) per pinnately compound leaf, having faded green to yellowish green autumn color
-trees will often drop a slow but continuous stream of leaflets, rachises, and entire leaves from mid-summer through early-autumn (before the advent of normal autumn leaf abscission), in response to both abiotic and biotic stresses
-trees cast a light dappled shadein youth, but a much more dense shade with maturity |
Flowers
-creamy-white to yellowish-green large inflorescences blanket the tree anytime from early Aug. to early Sept., with about a 3-week bloom period
-young seedling trees may not flower for the first 10 or so years unless the cultivar 'Regent', which flowers at a young age, is used |
Fruit
-thick green pods mature to yellow-green fruits, with the large beans appearing as knobs within the otherwise thin pods, hanging profusely from the tree
-ripening in Oct.-Nov. and persisting into Dec. or beyond |
Twig
-bright green in spring on the emergent stems, becoming kelly green to medium green in summer, and persisting as a dark green during the winter, remaining so for several years afterwards on the young branches, slowly fading to tan on the mature branches |
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Trunk
-branches are lightly furrowed and yellowish green-brown, but appear as if they are striated (i.e., having light brown, diffuse, straight lines on the lime green bark)
-trunks have interlacing ridges and are more deeply furrowed, becoming light brown to gray-brown with maturity
-wood is relatively weak, and the branches are prone to storm damage (with or without cankers and wood rot) with their increasing age and weight
-growth habit is very rounded, resulting from the loss of the central leader at an early age (for the species form) |
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C U L T
U R E
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Culture
-full sun to partial sun
-performs best in full sun in moist, well-drained soils of average fertility, but is very urban tolerant (especially to heat, drought, pollution, compacted soils, and poor soils)
-species form is propagated by seed, and cultivars are budded onto seedling understock
-several potential diseases (including branch and trunk canker [which can lead to wood rot and storm damage] and twig blight [which leads to leaf abscission and stem dieback]) and at least one potential pest (potato leaf hopper [which kills the new growth, leading to the resultant regrowth as witches' brooms])
-low availability, in B&B form |
Hardiness
-zones 5 to 8
Origin
-native to the Orient
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U S A G E |
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Assets
-showy creamy inflorescences in mid- to late-summer
-rapid growth rate
-urban tolerance
-dappled shade in youth
-wildlife attraction when in fruit
Liabilities
-fruit abscission (and bird deposition of fruit residue) from Oct. through Dec., a true liability if the tree is sited near parking lots, sidewalks, etc.
-continuous sequence of dropping leaflets, rachises, flowers, fruits, and pedicels from July through Dec., and dead stem abscission year round
-weak wood and brittle stems, often resulting in storm damage with age
-potential for numerous diseases and pests
-species form is slow to flower as a young tree in the northern areas of its range
-poor autumn color
-marginally hardy in severe zone 5 winters, exhibiting twig dieback |
Function
-shade, specimen, or summer-flowering focal point
Texture
-medium texture in foliage and when bare
-thick density in foliage and when bare |
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S E L
E C T I 0 N S |
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Varieties
and Cultivars
- Search
OSU PlantFacts for additional plants in this species
Alternates
-medium- or large-sized shade trees with showy flowers in summer (Koelreuteria paniculata, Liriodendron tulipifera, Magnolia grandiflora, etc.)
-urban tolerant shade trees (Acer platanoides, Fraxinus pennsylvanica, Gleditsia triacanthos, Quercus rubra, etc.) |