Poison ivy vines appear “hairy” and “raggy.” The rhyme “Hairy rope, don’t be a dope” was cited in print in 1996 and “Hairy vine, no friend of mine” in 2008.
Similar poison ivy rhymes include “Leaves of three, let it be,” “Leaves of five, let it thrive,” “Berries white, a poisonous sight” and “Raggy rope, don’t be a dope.”
Wikipedia: Toxicodendron radicans
Toxicodendron radicans, commonly known as poison ivy (older synonyms are Rhus toxicodendron and Rhus radicans), is a poisonous North American plant that is well known for its production of urushiol, a clear liquid compound found within the sap of the plant that causes an itching, irritation and sometimes painful rash in most people who touch it. The plant is not a true ivy (Hedera).
Various mnemonic rhymes describe the characteristic appearance of poison ivy:
1."Leaflets three; let it be” is the best known and most useful cautionary rhyme. It applies to poison oak, as well as to poison ivy.
2."Hairy vine, no friend of mine.”
3."Longer middle stem; stay away from them.” This refers to the middle leaflet having a visibly longer stem than the two side leaflets and is a key to differentiating it from the similar-looking Rhus aromatica (fragrant sumac).
4."Raggy rope, don’t be a dope!” Poison ivy vines on trees have a furry “raggy” appearance. This rhyme warns tree climbers to be wary. Old, mature vines on tree trunks can be quite large and long, with the recognizable leaves obscured among the higher foliage of the tree.
5."One, two, three? Don’t touch me.”
6."Berries white, run in fright” and “Berries white, danger in sight.”
12 July 1996, Washington (DC) Times, Tangled in painful reality of poison ivy”:
“Hairy rope, don’t be a dope”—heard that one?
New York (NY) Times
SOAPBOX; A Kid’ll Eat Ivy
By SUE FERRARA
Published: August 26, 2001
Then I moved to New Jersey, where my kindergartener came home knowing how to draw pictures of poison ivy and poison oak. She and my 12-year-old learned the rhymes: Leaves of three let it be. Hairy rope—don’t be a dope.
26 Jan 2008
“Hairy Vine, No Friend of Mine”
by Pam in Plants, Tree
I know I have poison ivy in various places around my backyard, but I didn’t know for sure until looking for things to photograph recently that it is one of the vines growing up the Shagbark Hickory in my backyard.
7 May 2008, Rochester (NY) Democrat and Chronicle, “Health Checkup: Local Advice” by Les Moore, Living, pg. C2:
An old mnemonic is, “Leaves of three, let it be; hairy vine, no friend of mine.”
Connecticut Post (Bridgeport, CT)
Beware of the pretty poison
Published 5:27 pm, Thursday, June 10, 2010
Many of us learn to identify it through descriptive nursery rhymes: “Leaves of three, leave them be.” “Raggy rope, don’t be a dope.” “Hairy vine, no friend of mine.” How many of these are you familiar with?
The Poison Oak and Poison Ivy Survival Guide
By Sandra J. Baker
Medford, OR: Coleman Creek Press
(leaves changed to leaflets for botanical accuracy)
Leaflets three, let it be; leaflets five, let it thrive.
Berries red, have no dread; berries white, a poisonous sight.
Hairy vine, no friend of mine. (poison ivy vines)
Raggy rope, don’t be a dope. (poison ivy vines)
Red leaves in the spring, it’s a dangerous thing.
Side leaves like mittens, will itch like the dickens.