Poi­son ivy, the sneaky plant

Rappahannock News - - EDITORIAL & OPINION - Pam Owen [email protected] gmail.com

As a kid grow­ing up in Vir­ginia, I learned early to spot the trio of shiny leaves – “leaves of three, let it be” – that spelled dis­as­ter if I touched it. Al­ready prone to con­tact der­mati­tis, when I brushed up against poi­son ivy ( Tox­i­co­den­dron rad­i­cans) I could expect my re­ward would be a per­sis­tent rash that itched and oozed, lead­ing to sleep­less nights and mis­ery for weeks in the hot, hu­mid days of summer. And even if I was care­ful, my dog wasn’t. Im­per­vi­ous to urush­iol, the oily sub­stance that trig­gers the itch, all my dogs have been happy to share it with me.

Urush­iol is also found in other na­tive plants in the Tox­i­co­den­dron genus, in­clud­ing Poi­son Oak and Poi­son Su­mac, but poi­son ivy is more per­va­sive and a shape shifter. It takes the form of a shrub when no up­right sup­port is avail­able, of­ten blend­ing into Vir­ginia’s sub­trop­i­cal tan­gle of plants along for­est edges. When trees are avail­able, T. rad­i­cans can wrap its hairy vines around them, grow­ing sev­eral inches thick as it climbs up the tree. Be­ing the only na­tive vine that’s hairy, at least it’s eas­ier to spot in that form.

Ac­cord­ing to the Poi­son Ivy, Oak, and Su­mac In­for­ma­tion Cen­ter (poi­sonivy.us), the name “poi­son ivy" was coined by Cap­tain John Smith in 1609, and the ear­li­est pub­lic records of the plant date back to that era. Not an ivy at all, it is ac­tu­ally in the pecan plant fam­ily ( Anac­ar­diaceae). Although it doesn’t pro­duce tasty nuts, T. rad­i­cans is im­por­tant to an ar­ray of wildlife that feed on its flow­ers and, in the fall and through the win­ter, on its whitish berries.

Un­like some other plants and an­i­mals that are be­com­ing extinct as tem­per­a­tures rise glob­ally, T. rad­i­cans is quite happy with in­creased car­bon diox­ide in the at­mos­phere and the rise in heat it causes. Duke Univer­sity sci­en­tists ( ni­cholas. duke. edu) who dis­persed car­bon diox­ide into the air in test plots in Duke For­est at lev­els sim­i­lar to those pre­dicted to oc­cur on Earth in 2050 found that poi­son ivy grew 149 per­cent faster and pro­duced a con­cen­tra­tion of urush­iol that was 153 per­cent higher than vines grown in con­trol plots.

There are a va­ri­ety of ways to com­bat con­tact with urush­iol. On fam­ily ap­ple-pick­ing out­ings in the western Pied­mont, I usu­ally brought back rashes along with ap­ples un­til an or­chard owner sent me down to her spring with a bar of lye soap to scrub my­self be­fore go­ing home. While lye soap can re­move urush­iol, there are other sub­stances avail­able that are kinder to the skin. Jew­el­weed, a com­mon na­tive

Measles make you bumpy And mumps'll make you lumpy And chicken pox'll make you

jump and twitch A com­mon cold'll fool ya And whoop­ing cough

can cool ya But poi­son ivy, Lord'll make

you itch!! plant, was likely used by na­tive peo­ple be­fore Euro­peans ar­rived but seems to have had a re­birth in pop­u­lar­ity and is now easy to find in soap form. Tecnu, a man­u­fac­tured prod­uct, also works well for me. What­ever the strip­per, it should be used as soon as pos­si­ble af­ter ex­po­sure.

A va­ri­ety of reme­dies are also avail­able for get­ting rid of the rash af­ter the fact, although I’ve never found any

to be par­tic­u­larly use­ful other than to re­lieve the itch a bit. As the In­for­ma­tion Cen­ter points out, “Ev­ery­one ap­pears to re­act slightly dif­fer­ent to all the reme­dies.”

I’ve had a lot of dis­cus­sions over the years about how many peo­ple are al­ler­gic to poi­son ivy. Sources vary, but the range seems to be from 15 to 50 per- cent. Ac­cord­ing to most sources, the al­ler­gic re­ac­tion seems to come down to the fre­quency and con­cen­tra­tion of ex­po­sure – the more con­tact, the more our im­mune sys­tems are likely to re­act. Only con­tact with urush­iol can cause the rash, so if the oil can be thor­oughly re­moved in time, a rash won’t oc­cur. If urush­iol is re­moved af­ter the rash ap­pears (not a pleas­ant process), the rash will not spread. Burn­ing poi­son ivy is bad idea be­cause breath­ing in the smoke can cause an al­ler­gic re­ac­tion in the lungs, ac­cord­ing to a Na­tional In­sti­tute for Oc­cu­pa­tional Safety and Health pam­phlet, “Pro­tect­ing Your­self from Poi­sonous Plants” (cdc.gov/niosh) which of­fers sug­ges­tions on deal­ing with ex­po­sure to urush­iol.

While it’s good to re­mem­ber that the tri-leafed stems of poi­son ivy help in iden­ti­fy­ing it, there are other plants with sim­i­lar struc­ture, and its leaves are not al­ways shiny or red and can be a lovely matte green – and the plant can take sur­pris­ing forms. I was re­minded of that one day when my brother and I, walk­ing down around one of the lower ponds, saw a branch over our heads that we couldn’t eas­ily iden­tify. I took hold of the branch to get a closer look at the leaves.

The branch was more than 10 feet long and ap­peared at first glance to be grow­ing out from a 30-foot tree. It had lovely smooth, gray bark and three leaflets on each stem, with the main stem longer than the one with the other two leaflets. I thought of poi­son ivy but dis­missed it be­cause the branch seemed to be com­ing from the tree.

While I was look­ing at the leaves, my brother tracked back to the tree and found it came from one of sev­eral thick, in­ter­twin­ing poi­son ivy vines wrapped around the tree and ex­tend­ing more than 30 feet up to near the crown. The leaves that were left on the tree, a Black Lo­cust, were barely dis­cernible through the thick fo­liage of the poi­son ivy. For­tu­nately, I had not touched the leaves, and the bark of the branches is less likely to have urush­iol than the rest of the plant, but I still scrubbed my hands with jew­el­weed soap when I got back to the house.

So, keep your eyes peeled, think be­fore you touch any plant, and keep the jew­el­weed soap, Tecnu, or both handy. It’s go­ing to be a long, hot summer.

Photo by Pam Owen

Poi­son ivy leaves ap­pear to be grow­ing out of a black lo­cust, but a closer look re­veals the branch came from huge in­ter­twined poi­son ivy vines.

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