Photographer: Flickr user Dendroica cerulea.
Original URL: http://www.flickr.com/photos/dendroica/9455616920/
Shared under Creative Commons BY-2.0
This is an aggressive deciduous tree than can grow to 80′ tall. The gray bark of Tree of Heaven (Ailanthus altissima) is smooth and the alternative compound leaves can bear 11-25 leaflets. Clusters of small yellow-green flowers appear in late spring near the branch tips. Female plants produce seeds in late summer that ripen to flat, twisted papery samaras that twirl as they fall. All parts of the plant have an offensive odor.
The plant is native to China and will spread both by seed and root sprouts, sending out suckers from cut stumps. A single tree can produce up to 350,000 seeds a year.
To control this invasive species, pull young plants before a long taproot is established, targeting female trees to prevent seedlings. Be sure to get all of the root and check back for several years to make sure you got the whole root.
Two locally native alternatives to Tree of Heaven are Bigleaf maple and Ponderosa pine (Willamette Valley stock).
