Koelreuteria paniculata - Golden Raintree
Family - Sapindaceae
Size - Medium sized tree, 25 to 30 feet in height with a equal spread. Growth rate is approximately 1 1/2 feet per year. Branches spreading and ascending.
Foliage - Alternate, pinnate or bipinnately compund. Dark green. Fall color is yellow.
Flower/Fruit/Seed - Flowers themselves are yellow and in panicles 12 inch long and about as wide. Flowering occurs in north Alabama in late June - early July. Flowering is very showy. Flower panicles evolve to papery 3 valved capsules turning color from green to yellowish and then brown. They persist on the tree into the fall. Seeds, 2 per valve, are black and shiny and about the size of a english pea. The capsules are often called 'Japanese lanterns'.
Bark - Dark brown, heavily ridged and furrowed on older trees.
Pests and Diseases - Nothing particularly serious. Boxelder bug gravitates to it in the fall of the year and congregates on the southwest exposures. The species in the eastern half of the US is not a threat to the plant and is more of a nuisance than anything. From my understanding, there are other species which are prevalent in the western US that can be damaging to ornamentals and fruit trees. Supposedly somewhat weak wooded but I have never noticed any damage to Goldenraintree as a result of high winds nor ice storms.
Landscape Use - Seen quite a bit in the residential, municipal, and commercial landscape nationwide. Makes a good mid sized accent tree. One of the few yellow flowering trees, and as a bonus it occurs in the summer when little else is flowering. Not real long lived in urban use, I would expect 25 to 30 years from one as an average. Withstands drought, heat, wind, alkaline soils, and tolerates air pollution. What more could you ask? As a result it is a very heavily used, (almost over used) tree.
Performance - 9 Hardy from zones 5 to 9.