Golden rain tree
Taiwan native, Koelreuteria elegans,is a very popular landscape tree because of its colorful petals and rose colored fruit capsules. Even though this tree is loved and valued by many, we cannot ignore the invasive characteristics that initiated its appointment as a Category II exotic invasive. Koelreuteria is a fast growing plant that is able to grow in an array of environmental conditions.
Koelreuteria elegans is a deciduous tree that grows 25 to 50 feet in height, with a 35 to 50 foot diameter spread. The bark is furrowed lengthwise and corky. Leaves are bipinnately compound, ovate to oblong in shape, and arranged alternately on the stem. Flowers are yellow, 12 to 20 inches long, 8 to 10 inches wide, and densely pubescent. Fruit is oval but elongate in shape, varies in length from 1 to 3 inches, and is pink in color. The fruit can also be described as being an inflated papery capsule. Seeds are small and black.
Introductions of Koelreuteria as an ornamental tree have made it possible for this tree to escape from cultivation and naturalize in Texas, Louisiana, Alabama, and Florida. Because it is a fast grower and has greater seed viability in warmer climates, Koelreuteria has the ability to crowd out desired native species.
The first step in preventative control of Koelreuteria is to limit planting and removal of existing plants within the landscape. If possible, removal should occur before seeds are produced.
Inform the public to refrain from purchasing, propagating, or planting Koelreuteria due to its ability to escape into natural areas.
Larger trees may be cut, should be coupled with chemical treatment to avoid resprouting. Small seedlings may be mowed or pulled by hand.
There are no known biological control programs for Koelreuteria elegans.
There are no known chemical control programs for Koelreuteria elegans. Cut stump treatments with 100% triclopyr-amine are effective but should be applied to the outer lay of bark within 1 minute of cutting. Foliar applications have not been tested for control of this species.