Koelreuteria elegans (SAPINDACEAE) Golden Rain Tree, Chinese Rain Tree

Weeds to Whack

Golden Rain Tree is a hardy, fast-growing tree well adapted to Australian conditions. It is native to Taiwan and thrives in temperate climates. First recognised as a naturalised environmental weed in the 1990s in the Brisbane City Council area where it has invaded urban parks, bushland, gullies and streets. Naturalised in the USA and in Japan. Both Koelreuteria paniculata and K. elegans sp. formosana have been widely planted in Australia. Compound leaves of K. paniculata have coarse, rounded serrations on the edges and are divided by a common axis, whereas those of K. elegans sp. formosana have pointed serrations and are divided twice.

Photo: Robert Whyte

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Seed capsules of K. paniculata are cone-shaped, in contrast to those of K. elegans sp. formosana a which are more egg-shaped. Leaves are dark green, hairless, above and paler green below and of variable size and shape. Leaflets are narrow, ovate (pointed at one end and rounded at the other), and have irregularly toothed edges and a long, tapering point. Flowers are small, butter yellow with five petals, to 20 mm in length, and occur in branched clusters at the stem tips. Fruit is an inflated papery capsule that splits into three parts and is light pink to deep rose in colour, up to 50 mm long and appear in large drooping clusters. Seeds are small, black and round and about 5 mm in diameter. Seedlings are often found beneath mature trees. It tolerates full sun, partial shade, drought, frost, heat, well drained to wet soils, extended flooding and air pollution. The potential distribution includes Western Australia and the Northern Territory. When weeding take care, as seedlings of the native White Cedar Melia azedarach can be mistaken for Golden Rain Tree seedlings.