SEMINOLE COUNTY RESIDENTIAL HORTICULTURIST
Fall is here. Golden rain trees are blooming all over the places. It is very exciting to see the trees covered with yellow flowers announcing the change of season. Golden Rain trees belong to the Sapindacea or soapberry plant family, which include the lychee, Spanish lime (mamoncillo), and longan. The Golden Rain trees are grown for their extraordinary display of beautiful yellow flowers and reddish fruit pods that appear later in the season in Central Florida. The flowers start to appear in September and are produced in very showy panicles, visible above the foliage, often covering the tree. It is easy to see why they are called golden rain trees as you watch the large quantity of small yellow petals falling to the ground.
The tree: Golden rain trees are deciduous and grow about 30 to 40 feet tall. Leaves are pinnately compound with leaflets mostly serrated. The small, yellow, fragrant flowers, that last about two weeks, are borne in terminal panicles measuring 1.0 to 1.5 feet long. The fruits, about 2 inches long, resemble Chinese paper lanterns and contain three round black seeds. The seedpods are colored pink, salmon or shades of red, before turning tan-brown. Seedpods can hang on the tree for several months. It is not unusual to see the blooms and seed pods on the same tree, at the same time.
Species: There are 3 species of golden rain trees cultivated in Florida. The common golden rain tree or Varnish tree, Koelreuteria paniculata, has single pinnate compound leaves, and flowers with 4 petals. This tree is the most widely cultivated specie because of its freeze tolerance. The Chinese Flame tree or Bougainvillea Goldenraintree, Koelreuteria bipinnata, has twice-compound leaves, and flowers with 5 petals. The other specie, Koelreuteria elegans has bipinnate, continuously serrate leaflets and flowers with 4 petals. K. elegans and K. bipinnate are typically found in central and south Florida, while K. paniculata is grown more in the northerner parts of the State.
Culture: Trees grow best in full sun in a wide range of soil types and pH. Established trees have a high drought tolerance. Trees require pruning to develop a strong structure. Dead wood is often present in the canopy and should be removed periodically to maintain appearance. Roots grow deep and are noninvasive.
Propagation: Plants can be propagated from root cuttings or seeds. Seedlings can be found growing under adult trees.
Use: Goldenrain trees can be successfully grown in urban areas where air pollution, poor drainage, compacted soil, and drought conditions are common. It is recommended for parking lot islands, buffer strips around parking lots or for median strip plantings in the highway. It is an excellent specimen tree, with some value as shade tree or residential street tree. The seedpods maintain their color after drying and are often used in everlasting floral arrangements.
Problems: Occasionally, scale insects may affect this tree. Sprays with horticultural oils can control the overwintering stages. Jadera bugs, often called golden rain tree bugs, feed on this tree and may build up large populations becoming a nuisance to people living near this tree. Immature stages of the insect are red in color, turning black when becoming adults. These insects are sap feeders but are not considered serious pests for the tree. Chemical control is not usually recommended but, if necessary, Sevin, Malathion, Orthene or other low toxic insecticides can be used to control them. Canker, a fungal disease, causes dead and sunken areas on the bark. Minute pink fungal structures may develop on the diseased bark. Seeds germinate readily and may create a weed problem. Because its wood can break easily in windy weather, it should be planted in wind protected areas.
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