Tree of Heaven is a non-native that has been planted as an ornamental but has escaped and is now moving into disturbed sites. The Colorado Department of Agriculture is considering adding it to the weed list in 2022.
Flowers are small and yellowish green. Usually unisexual. Female flowers are ill-smelling. The flowers are arranged in 4 to 7 inch long inflorescence at the tips of short branches.
Photo: Jan Samanek, Phytosanitary Administration, Bugwood.org
Single seeds in a 1 to 2 inch long, propeller-shaped fruit. Fruits are straw to reddish brown colored. They form in large bunches, each containing hundreds of seeds that are easily dispersed by the wind.
Photo: Annemarie Smith, ODNR Division of Forestry, Bugwood.org
Compound leaves are 1 to 3 feet long with 10 to 40 leaflets. At the base of each leaflet are 2 to 4 rounded teeth with a rounded gland on the lower surface. The glands secrete a sugary substance. Photo: Annemarie Smith, ODNR Division of Forestry, Bugwood.org
Grayish bark is relatively smooth. It tends to resemble cantaloupe when mature. Trees grow to 60-70 ft tall and the trunks to 20 feet diameter.
Photo: Richard Gardner, Bugwood.org
Branches are alternate. The pith is soft, with a peanut butter appearance. The leaf scars are prominent and heart-shaped.
Photo: Leslie J. Mehrhoff, University of Connecticut, Bugwood.org