UF/IFAS Okeechobee County Extension Service

458 Highway 98 North

Okeechobee, FL 34972-2578

Phone: (863) 763-6469

E- mail:  dfculbert@ifas.ufl.edu

Quick LinksRelatives  Identification  rash prevention  Ivy removal  References    

Feature Article - for release the week of August 6, 2006

Dan Culbert - Extension Horticulture Agent

Scratch out Poison Ivy

Last week an office visitor asked to see a picture of Poison Ivy – he had been working in an overgrown area and thought he’d seen something familiar.  Next he rolled up his shirt sleeve and showed me a raging rash.  The claim was, “I never got it before, so I didn’t think it was poison ivy.”

Poison Ivy is found in Florida Yards, along fence lines, in natural areas and, yes, even by the beach.  Everyone needs to know this native plant is well established here.  And for many, touching this plant or its relatives will result in skin rashes.

Being able to identify this plant is a first step in avoiding this poisonous plant. It’s also necessary to scratching out this weed from Florida Yards.  I wouldn’t suggest you bring in a specimen for positive ID.  Instead, take a look at the pictures in UF Extension Agent Pat Grace’s Poison Ivy bulletin, available at our office, or sneak a peek at the photos on our website.

A relative problem

Many people get rashes that look like that of poison ivy, but swear “they were nowhere near it”.  Several relatives of this itchy invader are also found in our area.  These include edible plants such as the mango, pistachio and cashew, the invasive-exotic Brazilian Peppertree, and native sumacs and Poisonwood.  Therefore, if you get a rash from poison ivy, be careful with mangos and be prepared when chopping out those problematic Peppers from your Florida Yard.

Our Eastern Poison Ivy has the name Toxicodendron radicans, although some may call it Rhus radicans.  Any way you call it, look for a climbing woody vine that can live for many years. The stem has small aerial roots that let it cling to upright trunks of trees or palms and walls. This is a common plant in local woodlands.

When cabbage palms are moved from the wild into the landscape, poison ivy vines can also be transplanted with them.  Less common is the appearance of a seedling under powerlines, courtesy of one of our feathered friends.

Be careful if palms from the wild are transplanted to your yard. They may also bring this unwanted viney visitor.  Photo: Dan Culbert, UF/IFAS

The three shiny leaflets (inside the red circle) are all one leaf.  Note that Poison Ivy foliage turns red when it is stressed by poor growing conditions. Photo: Dan Culbert, UF/IFAS

Clusters of yellowish berries in the fall contain the gray seed of Poison Ivy.  Photo: Steve Baskauf, University of Tennessee Herbarium

These poison ivy vines have been have been cut and are dead, but they still contain the sap that causes rashes. Photo: Dan Culbert, UF/IFAS

Leaves of three let them be.

The leaf of this plant, or more correctly, the leaflet, is quite variable in shape.  Most have heard of the adage: "leaves of three let them be."  Poison ivy leaves actually consist of three shiny leaflets.  Individual leaflets measure from two to four inches long and are pointed at the tip.

Poison Ivy is often confused with other multiple leaved plants. A common look-alike is another native vine, Virginia Creeper, which has five dull-green leaflets.

Virginia Creeper is a woody vine with five leaflets. Berries will mature to a blue color, and the leaves also turn red in the fall.  It's non-poisonous. Photo: Dan Culbert, UF/IFAS

 

Small yellowish-green flowers appear in the spring and grow in clusters right above the leaf stalks.  Seed-like fruits, with a soft fleshy covering, are one-quarter inch in size and grayish-white when the clusters ripen in the fall.  In winter, Poison Ivy leaves turn red and fall from the vine – but be aware they still have sap that can cause rashes.

The fruit of Poison Sumac, which is not native to our area, is also whitish in color.  The Sumacs found in our area have red fruit, and are important as a food source for wildlife.  Poison Oaks are likewise not found here in South Central Florida.

An Irritating oil

Inside these plants is a chemical called urushiol.  This toxin irritates skin and mucous membranes.  Some people are quite sensitive to the effects while others show no problems.  Sensitivity to the poison ivy relatives can also come and go as we get older. Urushiol has no effect on other animals, but pets may get this oil on their hair and carry it to us.

Susceptible people show intense itching within hours, or it may take several days after contact with the poison oil.  Skin inflammation and blisters then erupt on the skin.  Itching doesn’t spread the rash, but oil residues under the fingernail might “spread the red”.  And note that burning poison ivy plant parts is not a good idea: the sap in the smoke can spread the toxin.  

Preparing to rip it out

Extremely sensitive persons should ask for help when removing these plants.  If you expect exposure to these plants,  prepare with what you wear, and use the new lotions that prevent rashes.  Lotions and creams containing the active ingredient bentoquatam (e.g.: Ivy-Block) should be used before the weed-whacking begins.  When properly applied, 15 minutes before exposure to the poison ivy relatives, the symptoms may be eliminated.

Long pants and long sleeved shirts, fully enclosed shoes, with leather or canvas gloves are suggested.  If vines or branches are growing above, protective eye wear and a wide-brimmed hat should also be worn. Avoid brushing up against the plants as much as possible during removal operations. Protective clothing should be removed as soon as practical after exposure to these plants. Don’t mix these clothes with other laundry - the irritating oil could be transferred.

If accidental exposure to poison ivy occurs, a ten percent water solution of potassium permanganate applied 5-10 minutes after exposure may prevent rashes.  It should be followed by repeated washes with soap and cool water to remove the oily sap. Thousands of other folk-remedies also exist, but few work for everyone.  In case of severe reactions, get to a hospital or consult with qualified medical professionals.

Ivy removal

Hand cultivation and pruning (with gloves on) may work for small plants if the person is not fully sensitized.  This may be the best approach if weed killers would damage desirable plants growing close to this vine.

In most cases, herbicides are probably the better choice.  Many can be used directly on poison ivy leaves growing along fences.  Some granular herbicides are labeled for longer follow-up ivy control.  However, most of these pesticides will also injure or kill desirable trees that harbor these vines.

A technique that I like to suggest is to cut out a section of actively growing vine and promptly applying a legal herbicide to the bottom half of the cut stem to control resprouting.

Choose an herbicide only after reading the pesticide label.  At the time of this writing, some herbicides legally used on poison ivy relatives may contain 2,4-D, glyphosate, imazapyr, and triclopyr.  Some products are labeled for specific sites, and pesticide registrations change over time.  Check with your UF Extension service for current recommendations.

I’ve placed more information on our Okeechobee web page, http://okeechobee.ifas.ufl.edu.  If you need additional information on Poison Ivy, please email us at okeechobee@ifas.ufl.edu or call us at 863-763-6469.  Local residents can stop by our office at 458 Hwy 98 North in Okeechobee, and visit our Okeechobee County Master Gardeners from 1 to 3 PM on Tuesday afternoons.  

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Trade names, where used, are given for the purpose of providing specific information. They do not constitute an endorsement or guarantee of products named, nor does it imply criticism of products not named. The Florida Cooperative Extension Service - Institute of Food and Agricultural Sciences is an equal opportunity/affirmative action employer authorized to provide research, educational information, and other services to individuals and institutions that function without regard to race, color, sex, age, handicap, or national origin.  Florida Cooperative Extension Service / IFAS / University of Florida.  Larry A.  Arrington, Dean Last update: 08/04/2006 .  This page is maintained by Dan Culbert  

references

Culbert, Dan. Lookout for Poison Ivy.  Vero Beach: Press Journal, 9/9/98. http://okeechobee.ifas.ufl.edu/News%20columns/Poison.Ivy.htm

Grace,  Patricia and Lowe, Sherrie.  Identification of Poison Ivy, Poison Oak and Poison Sumac in Florida  ENH886 Gainesville: UF/IFAS Florida Cooperative Extension Service, April, 2003.  http://edis.ifas.ufl.edu/EP220 and http://solutionsforyourlife.ufl.edu/hot_topics/environment/poisonous_plants.html

McAvoy, Gene.  Poison Ivy - Bane of the Great Outdoors.  LaBelle: Hendry County Horticulture  News, 2000.   http://hendry.ifas.ufl.edu/HCHortNews_PoisonIvy.htm