Golden Raintree, Golden Rain Tree, or Panicled Goldenraintree

(Sapindaceae - Soapberry Family)

Form

• medium-sized ornamental tree or shade tree
• maturing at about 30' tall by 30' wide
• upright rounded growth habit, becoming more spreading with age
• rapid growth rate

Culture

• full sun to partial sun
• performs best in full sun in moist, rich, deep, well-drained soils, but is adaptable to poor soils, compacted soils, various soil pHs, pollution, heat, drought, and urban stress in general
• propagated by seeds or cuttings taken from roots
• Soapberry Family, with occasional trunk canker, but otherwise no serious disease or pest problems
• moderately available in ball and burlap or container form
• Golden Raintree is extremely sensitive to being transplanted in Autumn, and care should be taken to amend the soil, fertilize, water thoroughly, mulch adequately, and avoid Winter salt spray, to enhance survival chances during the first Winter, if transplanting cannot be delayed until Spring
• young trees (especially those recently transplanted) are sensitive to dieback or death in severe Winters, especially in its northern limit of zone 5, while established trees are much more Winter hardy

Foliage

• alternate, pinnately to bipinnately compound, emerging bronzed and quickly maturing to medium then dark green, with about 7 to 15 leaflets, with each leaflet crenate and sometimes lobed at the base
• often exhibits poor fall color, usually chartreuse to green, but is golden yellow in good years

Flowers

• one of the few trees to flower in mid-Summer, during early July
• many green-yellow to bright yellow small flowers combine to form a foot-long large and showy inflorescence (a panicle in this case, hence the specific epithet), with the individual flowers not opening all at once and having a prolonged two-week bloom period
• inflorescences are very attractive and exhibit a good contrast against the green foliage or blue sky

Fruits

• clusters of lime-colored three-sided pods form in Summer, and slowly change to beige then mature to medium brown by Autumn, lasting throughout the Winter and persisting into the following Spring, with each pod containing one to three round black seeds

Twigs

• light brown, somewhat zig-zag, with prominent leaf scars and lenticels, but with no terminal bud

Trunk

• single-trunked or multitrunked, but quickly losing its central leader(s) to yield an assymmetrical or irregular growth habit in youth, becoming rounded with age
• bark is light brown, ridged, and furrowed with age

ID Summary

• clusters of showy lime-green fruit pods in late Summer change to brown capsules in Autumn and persist throughout the Winter into the following season
• virtually the only tree to flower in mid-Summer (early July) in Northern climates
• growth habit in youth is gangly with a few sparse stout branches, becoming rounded with maturity, and often multitrunked (or single-trunked branching low)
• leaves are pinnately compound
• stems have no terminal buds

USAGE

Function

• specimen, small shade, focal point, or street tree

Texture

• medium texture in foliage and bold texture when bare
• thick density in foliage and open density when bare

Assets

• early July showy yellow inflorescences
• ornamental late Summer, Autumn, and Winter fruit pods
• good street tree based upon mature size, ornamental appeal, and moderate shade, although its gangly appearance while young and non-flowering may be an initial drawback
• rapid growth rate
• urban tolerance

Liabilities

• straggly appearance in youth, often having a leaning or asymmetrical growth of the few stems until interior and side branches fill out to give it a more symmetrical, rounded shape with maturity
• young trees may exhibit dieback or be marginally hardy in harsh Winters, especially in zone 5

Habitat

• zones 5 to 9
• native to the Orient

SELECTIONS

Alternates

• Summer-flowering trees (Albizia julibrissin, Lagerstroemia indica, Sophora japonica, etc.)
• urban-tolerant trees (Fraxinus pennsylvanica, Gleditsia triacanthos, Ulmus x 'Urban', etc.)
• street trees (Acer campestre, Malus cultivars, Tilia cordata, etc.)

Variants

• Koelreuteria paniculata 'September' - flowers in late August and early September, zones 6 to 9, rarely available in the nursery trade

NOTES

Translation

• Koelreuteria is named for Joseph Gottlieb Koelreuter, an 18th century German botanist.
• paniculata refers to the inflorescences (panicles) that contains the many small yellow flowers.

Purpose

• Golden Raintree is a mid-Summer-flowering medium-sized tree.

Summary

• Koelreuteria paniculata is a mid-Summer yellow-flowering, urban tolerant ornamental tree, good for its shade, flowering, and dry fruit appeal, with a rounded growth habit to 30' tall and 30' wide also making it a good street tree.