In the springtime, there are lots of flowering trees; less so in the summer. That’s why the Chinese flame tree (Koelreuteria bipinnata) is such a popular landscape tree. The long panicles of fragrant yellow flowers turn into eye-catching papery orange, red, or salmon-colored seed capsules that look like Chinese lanterns. The canopy provides dappled shade, which allows shade-loving plants to be grown underneath.
Once the tree—which is a moderate grower—is well established, it’s quite tough and can tolerate wind, air pollution, salt spray, heat, and drought. It has a deep, non-invasive root system so you can plant it near a patio or a driveway. However, keep in mind when selecting a location in your landscape that the tree spreads up to 35 feet.
One drawback of the tree is its weak wood that breaks easily under mechanical impact. Its lower limbs should be pruned out of the way of mowers and tractors. Also, remove horizontal limbs because they are susceptible to high wind.
|Botanical Name||Koelreuteria bipinnata|
|Common Name||Chinese flame tree, Bougainvillea golden rain tree, Chinese golden rain tree|
|Plant Type||Deciduous tree|
|Mature Size||20 to 30 feet height, 25 to 35 feet width|
|Sun Exposure||Full sun|
|Soil Type||Sandy, clay, loamy|
|Soil pH||5 to 7; highly acidic to highly alkaline|
|Flower Color||Golden yellow|
|Hardiness Zones||7 to 9|
|Native Area||China, Japan, Korea|
How to Grow Chinese Flame Tree
Chinese flame tree can withstand tough environmental conditions such as air pollution, drought, and a moderate amount of salt runoff, which is why it is often planted as a street tree in urban areas or parking lots.
The tree requires the most attention during the first couple of years until it is well-established. Because Chinese flame tree has an irregular growth pattern, it is important to prune and train it to encourage strong branch structure.
Chinese flame tree needs full sun, otherwise it becomes leggy and unsightly.
It is tolerant of a wide variety of soils but it does best in well-drained soil.
Regular moderate watering is needed until the tree is well-established, usually two or three years. After that, it has a high drought tolerance.
Temperature and Humidity
The tree has good heat tolerance. It cannot withstand temperatures below minus 0 degrees F.
Established trees usually don’t need fertilizer other than a light annual application in the spring. It helps to keep the tree healthy and better resist disease.
The goal is to have one central trunk from which strong branches spread out with ample space between them, in other words, an airy canopy.
If extra trunks grow at the base, remove them as well as any branches that are close together. In a mature tree, continue removing any lower branches that can get in the way of traffic, because the wood and the bark are easily damaged by mechanical impact
Chinese Flame Tree vs. Golden Rain Tree
There is another Koelreuteria species that is confusingly also called Golden rain tree (Koelreuteria paniculata). It was a popular specimen tree until it was classified as invasive in some parts of the United States because it easily reseeds itself.
Koelreuteria paniculata is hardy to zone 5 so it can tolerate colder winters than Koelreuteria bipinnata.
One sure way to tell the two species apart is by their leaves. Koelreuteria bipinnata has alternate bipinnately compound leaves, whereas Koelreuteria paniculata has single pinnate, compound, feathery leaves. Both have yellow flowers but the seed capsules of Koelreuteria bipinnata are more colorful than those of Koelreuteria paniculata.
If you live in a cooler climate, and don’t mind pulling a few volunteer seedlings underneath the tree or nearby, Koelreuteria paniculata can be a spectacular focal point in your yard.
Generally, the tree does not have common serious insect or disease problems. Old trees may develop root rot. Sometimes the bark gets canker. Cut out the affected branches and fertilize the tree the next spring. Fertilizing is also the only remedy if the tree gets verticillium wilt, a fungus that manifests itself by sudden wilting and browning of entire branches.