2.7 Poison Ivy / Oak / Sumac.


Photo: Toxicodendron radicans 4. Photo: Toxicodendron rydbergii 5. We're lucky in Finland in that we don't have any of these problem plants. But since it's asked every week in season it has to be in the FAQ, so what's in here is mostly pulled from rec.gardens archives 1992 - 1994, or from alt.folklore.herbs archives 1993 -, or taken off bionet.plants June 1995. If you wrote some text I've included here but you aren't mentioned please email - I'll be happy to mention you in the next posting.

2.7.1 How to recognize PI/PS/PO

From Kay Klier (klier.fern.com):

POISON IVY (Toxicodendron radicans = Rhus radicans = Rhus toxicodendron)

Found in a wide range of habitats, but in the midwest often seen in disturbed woods, roadsides, and flood plains. Most widespread of PI, PS, and PO.

Small, slightly woody plant, or shrubby, or vining. LEAVES ALTERNATE (= 1 leaf per node), TRIFOLIATE (= 3 leaflets), with pedicel (leafstalk) and the CENTRAL LEAFLET WITH PETIOLULE (= leaflet stalk). The lateral two leaflets are not distinctly stalked. Leaflets are a variety of shapes, but generally ovate or obovate (roughly apple-leaf shaped). Leaflets may be smooth-edged (entire), irregularly toothed, or shallowly lobed. Leaves of one variant look like small oak-leaves (but look again!).

Leaves apple-green and shiny in the spring, deep green and often dusty in the summer, turning a glorious reddish orange in the fall. Flowers tiny, whitish, in clusters; fruits white berries in late summer or fall.

Closest look-alike: Box-elder seedlings (Acer negundo), which has OPPOSITE, trifoliate leaves; the lateral two leaflets are often slightly stalked. Older box-elders generally have 5 leaflets per leaf.

POISON SUMAC (Toxicodendron vernix = Rhus vernix)

Shrub, to perhaps 15-20 ft tall, often branched from the base. LEAVES ALTERNATE WITH 7-13 LEAFLETS, lateral leaflets without a petiolule (leaflet stalk), TERMINAL LEAFLET WITH A STALK. MIDRIB OF THE LEAF WITHOUT A PAIR OF WINGS OF TISSUE THAT RUN BETWEEN LEAFLET PAIRS. More small, whitish berries in a long cluster. Usually in wetlands, Maine to Minnesota, south to Texas and Florida.

Closest look-alikes: Staghorn sumac, Rhus typhina, which has clusters of fuzzy, red fruits and toothed leaflets, and likes dry soils; Smooth sumac, Rhus glabra, with bright red fruits and slightly toothed leaves; much drier soil than PS.

POISON OAK (Toxicodendron diversiloba = Rhus diversiloba).

Reputedly the worst of the bunch. Erect shrub, usually about 3-6 ft tall (to 12 ft!), bushy, with ALTERNATE LEAVES OF THREE LEAFLETS, the LEAFLETS generally lobed slightly or as much as an oak leaf; CENTRAL LEAFLET STALKED. Leaves generally bright, shiny green above, paler below. Fruits are small whitish berries. Common on the west coast, esp. low places, thickets and wooded slopes. Occasionally a 5-leafleted form is found.

Steve Hix (fiddler.concertina.Eng.Sun.COM), in response to above:

>POISON OAK description...
If it were only that simple! In addition to that form, you can find poison oak growing as a vine (very like wild grape, but with smooth bark) up to six inches in diameter disappearing up into the tree tops near streams, or in thickets that look a *lot* like blackberry without spines, or sometimes as collections of leafless single branches (later the leaves appear, shiny and red, changing to oily green, and so on).
Fortunately, it doesn't seem to grow much above 5000' elevation.

2.7.2 How to avoid the rash

Difficult if you live near PO/PI/PS...
... the best way not to get the rash is to learn to recognize the plant(s) and avoid it (them) after that.

- You can even get a dose if a bunch of the leaves get dumped into a stream or pond ... the oil ends up floating on the surface of the water.
- Dogs / cats / horses can get it on their coats and you'll get it from them when you pet them barehanded.
- If you burn these plants and inhale the smoke you'll get a bad case of internal PI.

2.7.3 Why does it give you a rash? / Spreading the oil about

From Ron Rushing (f_rushingrg.ccsvax.sfasu.edu):

The irritant in poison ivy, poison sumac, and poison oak is urushiol. The rash you get is an allergic reaction. Everything I say below about poison ivy should also apply to poison oak and sumac. If you brush up against a healthy undamaged plant, you won't usually get urushiol on you. You usually have to come in contact with a damaged leaf. Almost all plants have damaged leaves - either from insects, weather, or from your stepping on them.

The oil is easily transferred from one place to another. For example, I got some on my shoelaces once, and I kept getting poison ivy on my hands for a couple of months. Once it is on your hands, it can, and will, end up anywhere on your body.

The rash from poison ivy can take up to 72 hours to appear after exposure, and is often spread on the body by taking showers while the oils are still on the skin.

Once you get the oil on clothing, it can sit for months and still cause a rash upon contact with your skin. For example, lets say you get some poison ivy oil on your boots, then put the boots away for the winter. Next spring you get out the boots and go for a walk - but not in the woods. A few days later, voila - your hands are breaking out from putting on your boots and tying the laces. As long as you've washed the original oil off your skin, the exudate from the blisters should not re-infect your skin. It's just exudate, and does not contain urushiol.

From krrobert.uiuc.edu (K. R. Robertson):

Washing with strong soap merely removes excess poison from the skin, but will not remove any which has already reacted, because the poison is believed to form a complex with skin proteins and therefore is not removable short of removing the skin! Even so, it is difficult to wash off this insoluble poison completely.

Eating a leaf of poison-ivy may have disastrous results. One may surpass the normal level of immunity by the first bite; in this case one is in for an internal case of poison-ivy, occasionally known to be fatal.

The mechanism of sensitivity is not thoroughly understood. It does not behave like protein sensitivities such as hay fever. It is a hypersensitivity of the delayed type, whose mechanism is related to that of organ transplant rejection.

(Originally prepared by William T. Gillis, 1973, Revised by Kenneth R. Robertson, 1993, Illinois Natural History)

Poison Ivy, oak, sumac: Clothes contamination
From: Gerry Creager <n5jxs.tamu.edu>

One thing a lot of folks don't seem to understand, especially now that a lot of laundry detergents are available for cold water use, is that HOT water is a good element for elimination of the oily residue that causes the allergic reaction. I noted several anectdotal comments about reinnoculation that could have been prevented if the contaminated clothes were washed in hot water (not warm, not warm/cold, HOT!) and alone so as to avoid cross contamination to other clothing. I've had good result with this in our family as well as in the folks I have advised with the problem. Me? I'm one of those who so far has not manifested an allergy despite a lot fo time in the woods!

From ab282.detroit.freenet.org (Robert Gault):

The active ingredient in poison ivy and other plants in the same family is 3-n-Pentadecylcatechol, common name urushiol, which is a chemical in the phenol family.

Dermatitis (skin inflammation and blistering) is spread by the act of scratching which redistributes the urushiol over the body. While the normal treatment for poison ivy does not include the suggestion below, a reasonable approach would be to convert the urushiol into a water soluble material. Phenols are acids so washing with a weak base like diluted house hold ammonia or a paste of baking soda should do the trick.

From Kay Klier (klier.fern.com):

People who react to any of the species of PI/PO/PS will undoubtedly react to the others; further, they may cross-react with mango (Mangifera indica), cashew (Anacardium occidentale), and Chinese or Japanese Lacquer (Rhus verniciflua). (the cellulose-based spray paint that is called lacquer is not involved in this... just "real" lacquer, like carved lacquer boxes, etc.). Generally speaking, it's not a good idea to sit under any member of the Anacardiaceae in the rain... they all tend to have a leaf toxin that falls on innocent bystanders below.

Most people are NOT sensitive to PI/PO/PS at birth, but become sensitized through repeated exposures. Some people are apparently immune throughout their lives, but I really don't know how to test that claim... ;-)

There is a barrier cream and a cleanup wash called Technu commonly used by those who are sensitized to PI/PO/PS. Works quite well.

2.7.4 What helps

First a word of caution:
The recommendations listed here are without medical foundation and, if actually used, are at the sole risk of the reader.

  • Jewelweed, Impatiens pallida, I. capensis, I. biflora, or similar species. AKA Touch-me-not, silverweed.
    The plant produces both cleitogamous (self-fertilized), and chasmogamous (cross- fertilized) flowers. Mature seed pods will build tension as they dry, and can "shoot" seeds 5 feet away when activated by a slight disturbance.
    • Jewelweed, fresh: crush some leaves and a bit of the stem and rub the resulting juice on the rashy area. Repeat frequently.
    • Jewelweed decoction: take one part Jewelweed (or stronger as needed), and twenty parts water. Boil water in non-metallic container, add jewelweed, boil for fifteen minutes, strain and store in jar in fridge or freeze as ice cubes. Apply frequently.
    • Jewelweed juice:
      From YE71.MUSIC.FERRIS.EDU (Robert King):
      • Gather the entire plant, leaves, stems, and all; the plant is very succulent and juicy... I have never had a need to add extra water, but if you do, use distilled. Don't be greedy, either trim tops & outer branches, or selectively take entire plants from the center of a crowded stand. One large (4-foot) plant should be adequate for the largest rash on one person. Plants will lose turgor and wilt quickly after cutting, this is OK, just makes it easier to emulsify.
      • Liquefy the plants in a blender at the highest speed possible. Then extract the juice by filtering thru cloth, common strainer, or fruit press... a little pulp in the mix won't hurt, this will settle out after a couple hours, anyway. Use immediately, or refrigerate... this stuff spoils rapidly at room temperature..!!
      • Apply the juice to the infected area with a common paint brush... I've found 1 to 2" size works best. Blow-dry the area as you apply it with a hair dryer on low heat... after several coats of 'paint,' an orange-colored "skin" will develop. This "skin" will protect uninfected areas against the poison ivy allergen.
      • Repeat this procedure as needed, especially first thing in the morning, and before bedtime. Be sure to use common sense in keeping any fluid that happens to come from blisters away from unprotected areas... yourself AND others. Keeping the infected area as dry as possible will hasten the healing; continue application until no more blisters are present... usually about 3 days.
      • Ironically, jewelweed favors growing in areas of similar habitat as poison ivy, therefore it can often be found nearby, preferring moist ground, near water, or often, even in shallow water. It grows rapidly in ideal environs, but usually doesn't reach significant size until mid-summer; therefore, it might pay to keep a bit frozen in the fridge from the previous year for early-season use. The extract tends to spoil rapidly, even at cooler temperatures, so I wouldn't recommend keeping it for much more than a week without freezing... the fresh solution works best, anyway.
  • Catnip: rub fresh catnip leaves on the affected area.
  • Mugwort (Jilara [jane.swdc.stratus.com])
    Pick two large handfuls of fresh mugwort (Artemisia vulgaris) and let infuse in 1 cup alcohol for overnight. Apply to affected area with a clean sponge/washcloth/q-tips/whatever every four hours. Dries it up quickly.
    Robert Gault reminded me that mugwort is a strong allergen (have I told you they keep track of mugwort pollen in the air over here?). To quote Robert Gault: 'Can you imagine the result if the poison ivy sufferer is also allergic to Mugwort?!' Ouch - yes, I can.
  • Aloe vera (Jilara [jane.swdc.stratus.com])
    Take a large leaf from the aloe vera plant you keep on your windowsill for burns. (If you don't have one, get one!) (NOTE: "aloe vera gel" sold commercially does NOT work!) Slice lengthwise to expose the juicy interior of the leaf. (This will give you an upper and lower leaf, with a juicy side to each.) Trim off leaf edges. Apply directly to affected area, juicy side against the sores. Bandage in place. Apply a new leaf every day until healed. This works phenomenally well, but you have to put up with bulky slabs of aloe vera leaf against the area. Which would you rather have: oozing sores or a succulent slab of leaf? Thought so. ;-) I can't laude this one enough! It works faster than any other remedy! And relieves the dreadful *itching*, too!
  • Gumweed Plant (Grindelia)
    Native Americans used the resin from the gumweed plant to treat poison ivy.
  • Baking Soda
    I swear by baking soda paste for poison oak. It not only soaks up the oozing mess, it completely stops the itching throughout the day.
  • Mixed alcohol liniment
    Take sweetfern, jewelweed, witch hazel, rubbing alcohol... Zip it all up in a blender until it's green and mushed, let it sit for two weeks (ouch! I know...not for THIS outbreak, sorry), strain it and voila, a marvy liniment.
  • Poison Ivy leaf
    From: bear.helium.Gas.UUG.Arizona.EDU (Soaring Bear), May 1994:
    Actually, this is just the time of the year to build up your immunity by nipping off a very tiny piece of poison ivy leaf (size of a head of a pin) and put in a capsule and swallow. Do 1-2 times a week. Stop if you start breaking out.
    Caution from krrobert.uiuc.edu (K. R. Robertson):
    Eating a leaf of poison ivy may have disastrous results. One may surpass his normal level of immunity by the first bite; in this case he is in for an internal case of poison-ivy, occasionally known to be fatal.
  • Salt (from bss8n.galen.med.virginia.edu)
    For the little initial blisters, I rub salt and burst them and leave the salt on to dry. They're history. Also salt worked on the moist areas of my face and under my nose where lye soap lather couldn't stay dried out long enough to dry out the rash. Works well on large surface rashes in case the blister stage grew untreated (but it didn't work on the "mini-mountain" reaction to p.i. that my mom got). MOST essential, leave the salt on to dry, adding more salt moistened with water to help create a paste that will stick as it dries, thus drying out that nasty, annoying p.i. The worse the spread, the longer the duration of salt/soap treatment alternated 12 hours to 1) dry out the present fresh redness, and 2) dry out *new* fresh red.
    Yep, you guessed it... the salt falls off everywhere. That's one reason I used the lye soap during bed hours. The other reason was that neither treatment, in a prolonged battle (1 ½ wks) stayed effective by itself, i.e. continuous dry-out, but alternating them did it. I've wondered why?
  • Lye soap (bss8n.galen.med.virginia.edu)
    - initially from a pioneer reenactment lady. The older/yellower the bar got, the less effective it seemed. Now, I've found it at the grungiest grocery store in town, a soap called Oxygon. Wet the bar and lather it up on the rash into a paste and let dry. Easier than the salt but since discovering salt, I tend to believe salt is more effective for me, at least with my initial tiny blisters, which is all I ever have to deal with now.

2.7.5 Jewelweed, Impatiens

Photo: Impatiens glandulifera 11. From Elizabeth Perdomo, ElizPer.aol.com:
Jewelweed is a plant I wouldn't be without here in the South, any time of the year! It works so remarkably well for Poison Ivy, Oak and Sumac, and for Fungal Infections, as well (try it on athlete's feet!). People are always getting inspired to rake up leaves in the middle of winter, and get into the roots or old leaves, producing the nasty itch. However, since the plant only grows in mid-late summer, this is what I do to keep a supply around...

Harvesting: Jewelweed is an annual, which means it flowers, produces seeds and then dies all in one year. Thus, I try to harvest Jewelweed well before flowering time, so it has a chance to regroup, flower and seed before frosts. To do so, I cut off (with knife or pruner) the top ⅓ of some of the plants, leaving many untouched. I don't pull or pinch the tops, as this often dislodges or pulls up the plant. If you take more than about the top ⅓, the plant may not have enough time to sprout side shoots and go to seed, thus diminishing future supply for you, others & the earth...

Preparing: Jewelweed is one of those plants which just doesn't dry well. It's too fleshy and juicy, and loses it's good qualities when dried. I make a strong infusion, by adding LOTS of the plant to a pot (non-aluminium) of boiling water. Then, I cover the pot, and allow it to simmer for at least 30 minutes. After simmering, covered, I put it into a blender or food processor and blend. Then, I cover the mixture again and allow it to cool to room temp. After cooling, I strain the mixture through a stainless steel strainer and/or cheesecloth. Then, if needed right away, I label and store part of the mixture in a jar in the refrigerator. The remainder, I freeze in ice cube trays. After frozen, pop the cubes into a zip lock bag and LABEL WELL with herb name/date before returning to freezer. Then, I have a winter's supply. The cubes also feel really good on especially sensitive areas, like on the face, between fingers, under arms and in private parts... I also use the fresh Jewelweed and make it into a tincture by filling a jar with the plant, and then covering it with 100 proof vodka. If you are going to use it exclusively for EXTERNAL use, it could be "tinctured" in rubbing alcohol.

Administering: Whether fresh, infused, tinctured or in ice cube form, apply Frequently!!! Cotton balls work well to apply the infusion or tincture. Yes, the tincture burns some, so I dampen the cotton ball 1st with water, then add the tincture. The alcohol also helps to dry out the ooze... If someone has a really bad, "systemic" case (not just a few bumps on their ankles or hands), I recommend that folks take the (vodka) tincture INTERNALLY, about ½ dropper 2-4 x Daily, in liquid, But for only 2-3 Days! (I don't recommend using this orally if pregnant or nursing.) It seems that the oral use in conjunction with frequent, liberal external use, can really turn a bad case of poison ivy around fast! Also, for "oozy" spots, cosmetic grade (French) clay can be sprinkled on as often as desired to help dry the spots out. Sometimes, I mix the clay with powdered oatmeal, and apply the mixture to absorb and sooth.

Elizabeth Perdomo

From: Peter Gail <PETERGAIL.AOL.COM>

Re: the post about jewelweed tincture: Be extremely careful in applying an alcohol extract of jewelweed on anybody. Over the past 8 years Steven Foster has reported one and I have observed 3 extremely severe skin reactions from such applications, in each case landing the person in hospital. Euell Gibbons also referred to the possiblity of allergic reactions to jewelweed tinctures.

Comment from Henriette: the frozen cubes don't have these risks.

2.7.6 How to get rid of poison ivy in your yard

Suggestions from rec.gardens/alt.folklore.herbs:

  1. Planting catnip should get rid of poison ivy.
  2. Goats. They are very effective, but in the end will be a bigger bother than the poison ivy. (Be suspicious if someone offers you free goats!)
  3. Poison ivy again: buy the super concentrated form of Round-Up and dilute to 3 times the recommended strength. (Well, hot damn! It killed off nearly every piece of PI in one application and only a few (about a dozen) plants returned a year later.)
  4. Pull it, but protect yourself (big plastic bag, disposable suit...) Immediately wash all clothes you used two-three times. Do not touch the plastic bag / disposable suit from the outside. Do not touch your clothes / boots / whatever from the outside before washing.