December 8, 2011

Urban Tree of the Year 2011: Goldenrain tree

There has been high interest in the post about the Callery pear and at least one of our readers has made a planting decision based on information contained in the article. If you are looking for another showy tree, consider Goldenrain tree (Koelreuteria paniculata).

Image: Goldenraintree courtesy of City of Troy, MI Parks and Rec (source)
The Society of Municipal Arborists (SMA) selected the species as the 2011 Urban Tree of the Year.  In addition to its flowering characteristics, SMA members valued its tolerance of drought and soil conditions "including pH extremes (4.5-8.0), coarse to fine texture, and compacted soils with low organic content and fertility."  The species is relatively insusceptible to disease and insect infestation.  The goldenrain tree bug (Jadera species), a native insect, is an occasional nuisance according to the University of Florida/IFAS Extension.  Early structural pruning was recommended to "correct" its decurrent form if the species will be used as a street tree.

Image: Goldenraintree courtesy of Salt Lake City Urban Forestry (source)
Goldenrain tree is also historically interesting.  On "June 12, 1809, Jefferson received seeds of Koelreuteria from France and had a tree growing from them two years later at his home in Monticello, Virginia," according to a statement written by Dr. Nina Bassuk of Cornell.  And from the Monticello House & Gardens website:
In 1809, Thomas Jefferson received seeds from his Parisian friend, Madame de Tessé. He reported back to her in March 1811 that a seedling "has germinated, and is now growing. I cherish it with particular attentions, as it daily reminds me of the friendship with which you have honored me."[2] Jefferson's tree was likely the first grown in America, and Jefferson made the earliest American citation of this tree.[3] Goldenrain trees are now naturalized at Monticello.

The scientifically-minded French Jesuit, Pierre d'Incarville, was one of the few privileged explorers allowed in China during the mid-18th century. It is believed that, while in Peking, he collected the black, pea-sized seeds of the Goldenrain tree, which he entrusted to a Russian caravan on a westward trek to Europe. The seeds would eventually reach the Jardin du Roi in Paris and were being grown by 1763. However, according to Joan Dutton, the tree was introduced in England in 1560.[4]

[1] This section is based on the Center for Historic Plants Information Sheet.
[2] 27 March 1811. Betts, Garden Book, 454-455.
[3] Denise Wiles Adams, Restoring American Gardens: An Encyclopedia of Heirloom Ornamental Plants, 1640-1940 (Portland, Oregon: Timber Press, Inc., 2004), 83.
[4] Joan Parry Dutton, Plants of (Colonial Williamsburg. Williamsburg: Colonial Williamsburg, 1979), 22.

3 comments:

  1. This is a lovely and extremely tolerant tree, but I am surprised that it received such an honor, only because it produces a prodigious amount of seedlings. Personally, I prefer K. bipinata because the seed pods are more colorful, maturing to pink instead of straight to brown.

    ReplyDelete
  2. Les, thanks for the comment.

    I looked up K. paniculata's characteristics in the USDA PLANTS database and the species "seedling vigor" is listed as high while the "seed spread rate" is listed as low and the "vegetative spread rate" is listed as none (http://plants.usda.gov/java/charProfile?symbol=KOPA).

    In photographs, the leaf of the K. bipinnata (Chinese flame tree) appears waxier than that of K. paniculata. Is this the case?

    ReplyDelete
  3. I never noticed, or looked for a leaf difference, but the color difference of the seed pods is very noticeable.

    ReplyDelete

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