Thursday, August 11, 2016


POISON IVY – The largest specimen in Chenango County

Donald A. Windsor

The largest specimen of Poison Ivy (Toxicodendron radicans) that I have ever seen anywhere is growing right here in Chenango County. It is about 40 feet tall with a spread (drip line) of about 15 feet across. One of its lianas (woody vines that root in the ground and climb up a tree) is the size of my wrist (7 inches circumference, 2 ¼ inches diameter). The Poison Ivy is climbing up a White Pine (Pinus strobus) with two trunks. Next to it is another White Pine with its own Poison Ivy. I refrain from giving the exact location of these specimens out of fear that some misguided do-gooder may destroy them.

Searches in the surrounding area have not found any more plants. Searches will continue.

Here are some photos of this specimen. The winter shots were snapped on 9 November 2015. The summer ones were snapped on 5 August 2016. Anne Altshuler is in some of the photos pointing.

Leaves and berries. 

The trunks of the 2 White Pine hosts. The Poison Ivy branches appear to be growing out of the pine trunks.

The ivy growing up 40 feet.


Lianas growing up the trunk.

Large liana with pine needles caught in its rootlets.

Large lianas. Note the crossing from one trunk to another.

References consulted:

Leopold, Donald J. ; McComb, William C. ; Muller, Robert N. Toxicodendron radicans. In: Trees of the Central Hardwood Forests on North America. An Identification and Cultivation Guide. Portland, OR: Timber Press. 1998. Page 420.

Symonds, George W. D. ; Merwin, A.W. Poison ivy Rhus radicans. In: The Shrub Identification Book. The Visual Method for the Practical Identification of Shrubs, Including Woody Vines and Ground Covers.. New York, NY: William Morrow & Co. 1963. Pages 240-243. Master Pages 74-77.