Koelreuteria is the name of a genus of trees native to Asia. The genus includes three species: K. paniculata, K. bipinnata, and K. elegans. These types of trees share similar characteristics but some have some slight differences in size and appearance. The genus Koelreuteria is classified under the Sapindaceae, or soapberry, family in the plant kingdom. The trees are perennials, living for periods greater than two years, and are deciduous, losing leaves, flowers, and other structures seasonally.
Plants in this genus tend to grow at a moderate to a rapid rate, and they can reach 30 feet (approximately 9 meters) in height and width. These types of trees are native to the Asian continent, mainly found in China and Japan. The three species were introduced to other parts of the world, including the United States. Koelreuteria is cultivated in different areas as a shade tree and grown for other ornamental purposes.
Koelreuteria paniculata is also known as the goldenrain tree or Pride of India. These trees are relatively hardy, and can grow in periods of drought or in windy areas. Small green-yellow or yellow flowers bloom on the goldenrain tree's branches. In the initial stages of growth, bronze leaves grow on the branches, and the color darkens to a deep green at maturity.
Koelreuteria bipinnata, known as the Chinese flame tree or Chinese golden rain tree, grows best with a full exposure to sunlight. Unlike K. paniculata, which has single compound leaves, the Chinese flame tree has double, or bipinnately, compound leaves. The tree produces green-yellow leaves, yellow flowers, and pink fruit. The vibrant colors of the Koelreuteria bipinnata render it an aesthetically pleasing landscape tree. The tree is also often planted in parking lot islands to provide shade for parked cars.
Koelreuteria elegans is also known as flamegold or Chinese rain tree. The tree is found in a few parts of the United States, mainly in southern Texas and Florida. Similar to other trees in this genus, the K. elegans produces dark green leaves. In early summer, small golden-colored flowers bloom on the tree, followed by clusters of rose-colored, papery husks commonly called "Chinese lanterns."
These types of trees are rather sturdy, as they can flourish in different environments. Koelreuteria plants are mainly cultivated in parking lots and throughout residential streets. The colorful trees provide a moderately dense shade. These types of trees can mature successfully in urban areas, which indicates that they can withstand air pollution and poor drainage common to cities. Some of the trees have weak branches, and they require frequent pruning and training throughout the grown process to develop a strong branch structure.