Koelreuteria elegans

Golden rain tree

Introduction

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.

back to top

Description

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.

Reproduction occurs via seed that is able to germinate fairly quickly, within a period of 6 to 8 days. Water may contribute to the spread of the seeds, although this has not yet been proven. Birds may also play a factor in the dispersal of the seed.

back to top

Impacts

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.

back to top

Management

Preventative:

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.

back to top

Cultural:

Inform the public to refrain from purchasing, propagating, or planting Koelreuteria due to its ability to escape into natural areas.

back to top

Mechanical:

Larger trees may be cut, should be coupled with chemical treatment to avoid resprouting. Small seedlings may be mowed or pulled by hand.

back to top

Biological:

There are no known biological control programs for Koelreuteria elegans.

back to top

Chemical:  

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.

back to top

References and Useful Links:

Floridata Homepage

University of Florida Center for Aquatic and Invasive Plants

University of Florida’s Cooperative Extension Electronic Data Information Source

Langeland, K.A. and K. Craddock Burks. 1998. Identification and Biology of Non-Native Plants in Florida's Natural Areas. IFAS Publication SP 257. University of Florida, Gainesville. 165 pp.

The Plant Conservation Alliance's Alien Plant Working Group. Weeds Gone Wild: Alien Plant Invaders of Natural Areas

Pacific Island Ecosystems at Risk (PIER). Plant Threats to Pacific Ecosystems

Gilman, E.F. and D.G. Watson. 1993. Koelreuteria elegans: Flamegold. Fact Sheet ENH-496, a series of the Environmental Horticulture Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, Florida.

Excerpted from the University of Florida, IFAS Extension, Circular 1529, Invasive Species Management Plans for Florida, 2008 by:

Greg MacDonald, Associate Professor Jay Ferrell, Assistant Professor and Extension Weed Specialist
Brent Sellers, Assistant Professor and Extension Weed Specialist
Ken Langeland, Professor and Extension Weed Specialist Agronomy Department, Gainesville and Range Cattle REC, Ona
Tina Duperron-Bond, DPM – Osceola County
Eileen Ketterer-Guest, former Graduate Research Assistant

back to top