Tuesday, April 11, 2017

Stopping to Sniff the Poison Oak Flowers

Used with permission Jeffrey Szilagyi photo

I've always been a little leery of sniffing the poison oak flowers. The small clusters of yellow-green flowers have such a sweet, heavy, resinous odor, it's almost narcotic. As I watched the native bumblebees frolic in their blossoms on Loma Alta Ridge, I wondered if the resulting honey might make one rather itchy. Or would it offer some homeopathic resistance? Or would it be a bit like the dark mad honey made from azaleas (or oleander) and make you crazy?

Luckily, I don't ever catch poison oak, unless I pet a stray dog, but I'm also not foolish enough to tease and taunt the bitter herb.... A neighbor once burned a scrub pile and wound up in hospital with severe double pneumonia.

After riding double with me on my old horse, my childhood friend Micaela got it internally in her bloodstream and we had to razor shave the volunteer pustules off her skin. It was like she was sprouting weird puffballs or something. Poor Micaela was on Prednisone tablets for weeks. Itchy doesn't even begin to cover it. I didn't even get so much as a blister.

My horse adored trail-side snacks of fresh sprigs of tender poison oak shoots. It's a wonder I escaped it...her slobbering all over the bit like that. All that prime-time exposure, and I manage to sidestep the evil weed. Deer too are fond of the tender shoots. But the likelihood of my trying to pet the deer is next to nil.

In his 1789 journal,  Historia de la California. the Spanish explorer, Clavigero, clearly speaking from first-hand experience, cursed poison oak with the name, yiedra, or hiedra maligna (malignant ivy—from the Latin, hedra). A Bohemian naturalist on one of the Spanish expeditions in 1791, Thaddeus Haenkeon thought it was the same poison ivy of the East Coast. Close, but no coconuts.

Scottish botanist David Douglas discovered poison oak in 1825 at Fort Vancouver (or 1830 on Vancouver Island). And at about the same time, ship's botanist of Captain Beechey's HMS Blossom, a Mr. Hooker, also discovered it at the seaport, Yerba Buena (San Francisco). It's also the original place name of Los Angeles; Yangna or Iyaanga—the poison oak place. Let's hope they didn't discover it the hard way.
 "The name ivy or “hiedra” was also used by early Mexican settlers in California who mistakenly thought poison oak was a kind of ivy. A little-known subspecies of poison ivy, T. radicans ssp. divaricatum, is native to southern Baja California and Sonora, Mexico. Our California poison oak was noted by another British explorer of the 19th century, Captain Frederick Beechey, who took samples back to England. Much to the chagrin of unwary gardeners, both poison oak and poison ivy were planted in English gardens for their graceful climbing habit and beautiful autumnal coloration.” —Herbalgram (American Botanical Council) V. 34: 36-42, 1995, W.P. Armstrong, W.L. Epstein, M.D.
The watershed definition seems to be that western poison oak (Toxicodendron diversilobum) grows along the West Coast, while poison ivy (Toxicodendron radicans) grows on the Atlantic seaboard. Atlantic poison oak, (Toxicodendron radicans var. pubens) too is a subspecies of poison ivy, which is sometimes conflated with poison sumac, a very different shrub, or tree, which even more toxic (Toxicodendron vernix).
There is poison ivy on the west coast but it's rare. There is also a western subsspecies of poison ivy (T. radicans ssp. rydbergii), that grows in the northern Cascades above 5000 feet, but not in California. And just to keep things lively, the two species have hybridized in the Columbia River Gorge. And there's Baja/Sonora's little known southwestern species, T. radicans ssp. divaricatum. The Spanish explorers call them all mala mujer, wicked woman.

There are also several itchy Asian relatives, but our western poison oak is the only native in its gene pool. West coast, or Pacific poison oak, whether bush or climbing shrub, grows from Baja to British Columbia in all types of habitats up to 5000 feet. Previously dubbed  Rhus Toxicodendron, R. quercifolia, R. lobata, or R. diversilobum, western poison oak now has its own genus: Toxicodendron diversilobum. Toxic tree.

Botanist John Howell observed that the toxicity of T. diversilobum obscures its merits:
"In spring, the ivory flowers bloom on the sunny hill or in sheltered glade, in summer its fine green leaves contrast refreshingly with dried and tawny grassland, in autumn its colors flame more brilliantly than in any other native, but one great fault, its poisonous juice, nullifies its every other virtue and renders this beautiful shrub the most disparaged of all within our region." —Wiki
Whatever you want to call it, don't mess with poison oak. Even when you don't get it, there's always a first time. The more you're exposed to it, the worse the reaction. There are stories of ancient twigs in herbariums still potent with the urushiol toxin (or arusiol oil, named after the Japanese lacquer, or varnish tree—a kind of sumac; urushi means lacquerware), some 100 years later. The toxin urushiol is not limited to poison oak:
Urushiol is an oily organic allergen found in plants of the family Anacardiaceae, especially Toxicodendron spp. (e.g., poison oak, Lacquer Tree, poison ivy, poison sumac) and also in parts of the mango tree.  —Wiki
I can personally attest to the irritant on the mango tree. Add mulberry, cashew, and stinky ginkgo to that list. I found myself humming, Underneath the mango tree, my honey.... and adapting other lyrics: Don't sit under the mango tree with anyone else but me...  Ah, my itchy-lipped college friend, Carolyn, who survived a springtime romp in a poison oak bush on Mt. Tam—how did she ever explain it to her doctor? I think that was finally the end of her and bad boy Carlos. I was luckier. But I still have to avoid the rind of the mango or I get itchy lips.

And then there are those rank amateurs, in search of a trail-side loo, who back up into the bushes... Whenever we go huckleberrying, we have a weird arms-raised prisoner surrender dance whenever we push headlong through the underbrush, no hand contact. Our endgame is to strip down on the front porch before God and the road, drop all our clothes into a garbage bag, and then streak to the shower to scrub down with Fels-Naptha, old school laundry bar soap in cool water.

My granny said it was the oil of larkspur in the soap that did the trick. But Fels-Naptha is made of sodium hydroxide, fats, and glycerine—no oil of larkspur, or naptha-benzene either. No magic formula. Just washes the potent oil off of everything. Stick to blue Dawn dish soap. Rinse off in the creek if you must. The sooner, the better.

In his book Poison Ivy, Poison Oak, Poison Sumac and Their Relatives, Edward Frankel provides a dizzying list of home remedies for urushiol rash: “ammonia, baking soda, bleach, buttermilk, castor oil, coffee, cornstarch, Epsom salts, gasoline, goat’s milk, gunpowder, hairspray, horse urine, iodine, kerosene, Lysol, marshmallow, meat tenderizer, nail polish, oatmeal, sodium bicarbonate, strychnine, tobacco, toothpaste, whiskey, and last but not least, zirconium.” Such a list, dermatologist Albert Kligman observes, “clearly reveals the profound emotional effects of therapeutic desperation.”  —from Leaves of Three: The Rash Success of Poison Oak 2013
Speaking of diversilo-bum,  only humans (and some primates) are affected by the toxin, poison oak leaves, flowers and greenish berries are toxin-free, they feed myriad birds, bugs, and browsers. Poison oak is a good source of phosphorus, calcium, and sulfur. All I can say is that it's a good thing we are not like the deer browsing on tender spring shoots. Otherwise we'd have another story to tell. We can't ask the deer and the birds if the bounty of the poison oak bush is like third inning chili peppers navigating the GI tract.

California Native Americans (who also get poison oak), used the sap to cure ringworm, remove warts, corns, and calluses, to cauterize sores; to stop bleeding; poultices were used to counter rattlesnake venom; a spring tonic of dried roots, or buds was used to treat dysentery and parasites. I read that  the supple twigs and shoots were woven into baskets, the ash, and soot was used as a black dye for sedge baskets, and ink for tattoos. (Though, knowing of the longivity of the toxic quality of poison oak twigs, I wonder if the basketmakiing part is true.)

Apparently the poison oak pollen does not carry the dreaded toxin, urushiol, and as a result, the creamy honey is nontoxic, but bitter, with citrus notes—or so it is said. Not gonna try it, thankyouverymuch. Also, those shedded fall leaves no longer carry the dread urushiol. The poison oak plant is stingy with its toxin, and thriftily recycles it. But I wouldn't recommend sniffing the flowers, or collecting those pretty leaves in fall. Just. Don't. Eating the honey will not protect you nor increase your immunity. (See Do bees make poison ivy honey?) The bad news is that the only thing to increase your immunity to poison is distance—fond hearts aside.

The other bad news is that poison oak thrives, not only in disturbed habitats, but is also one of the few plants to thrive in a CO2-rich environment, and as an added bonus, the toxic urushiol becomes even more potent. Chalk it up to the joys of global warming. Feeling itchy yet?

More of my bloggy bits—let's just say the red leaves were a siren call for one couple, who, I'm sure rued the day:
Poison Oak Bouquet

I'm sure you're just itching to learn more about poison oak and its relatives. See this great article on poison oak (I lifted some of my facts from it):

Leaves of Three: The Rash Success of Poison Oak 2013

Poison Oak | High Sierra Topix 2006

The Poisoned Weed: Plants Toxic to Skin 2004

Toxicodendron diversilobum Wiki Poison oak grows along the entire west coast from Baja to British Columbia. Toxicodendron radicans, or Eastern poison ivy looks different. There is a wiki entry for western poison ivy, as well, a subspecies of Toxicodendron radicans, that grows in the Cascade mountains of Washington state. but it still looks like poison oak in my book. Maybe that's the difference, western poison oak prefers the coast and doesn't grow in the Cascades at all, or the Sierras, above 5000 feet.

western poison ivy is native to most of Canada from the Maritimes to British Columbia, and most of the contiguous United States except the southeastern states, New Jersey, Delaware, and California. Toxicodendron rydbergii is a low growing shrub that can grow to 3-10 feet tall). Toxicodendron radicans (eastern poison ivy), is a trailing or climbing vine.

A poison ivy primer Smithsonian Insider has the clearest definitions of poison oak, and poison ivy (which has several subspecies, and varieties, hence all the confusion.)
  • Over time, individual botanists have named some 30 to 40 different species of poison ivy across North America. A recent and comprehensive study, however, has reduced that number to one species, Toxicodendron radicans, with 5 sub-species –T. eximium, T. divaricatum, T. radicans, T. rydbergii and T. verrocosum. “Poison ivy has a lot of structural diversity: I’ve seen a free-standing poison ivy plant with three-inch leaflets growing right next to a climbing poison ivy plant with six-inch leaflets. They may look different, but they are the same species,” Pell adds. “Its morphological characteristics are very diverse and change in different habitats.” Its many different physical variations appear to be different species but are not.
Poison Ivy vs. Poison Oak: How To Spot These (Ob)noxious Weeds  They're pretty similar. Poison ivy is diminutive, while poison oak is larger, the leaves are oily and more lobed.

Resources of the Pacific Slope: A Statistical and Descriptive Summary 1869

In Praise of Poison Ivy: The Secret Virtues, Astonishing History, and Dangerous Lore of the World's Most Hated Plant  2016

Poison oak is beneficial for many species  2013  ukiahdailyjournal.com

Herbalgram (American Botanical Council) A Critical Review of Herbal Remedies for Poison Ivy Dermatitis

Poison Ivy, Plants Ruehl, blog 2014

Contributions from the United States National Herbarium 1920

Mad Honey – The Alameda County Beekeepers Association

Plant Life in a CO2-Rich World - Scientific American

Do bees make poison ivy honey?

Old Blue Raw Honey


I've always been a little leery of sniffing poison oak flowers (sweet, heavy, resinous odor), and I do wonder if the resulting honey might make one rather itchy? Or be a bit like the mad honey made from azeleas (or oleander). Luckily, I don't get it but I'm also not foolish enough to tease and taunt it.... a neighbor burned a scrub pile and wound up in hospital with severe pneumonia. After riding behind me on my old horse, my poor childhood friend got it internally in her bloodstream (from scratching it too much), and we had to shave the blisters off her skin. My horse adored trailside snacks fresh sprigs of tender poison oak shoots. It's a wonder I ever escaped it...

Don't mess with poison oak. Even when you don't get it, there's always a first time.  

Thanks to Jeffrey Szilagyi for the blog post ideas....


Suzanne Nathans said...

Enjoyed your piece very much, some nice fun writing skills you have.

This confused me: "Speaking of diversilo-bum, though only humans over the age of five (and some primates) are affected by the toxin, poison oak leaves, flowers and greenish berries are toxin-free, they feed myriad birds, bugs, and browsers. " Are you saying that these parts don't contain urushiol? It's the stem and root that have it? As I said, I am confused!

Some friends wrote a song about "sister" poison oak: https://www.youtube.com/watch?v=cqI-A_tD2G8.

I always kind of cringe when I read that Europeans "discovered" something here. I dunno, must be a better word for something that First Nations people obviously had discovered long before Europeans came along. But the image of someone "discovering" poison oak does it's job: for those susceptible to it, the discovery must be really something.

Thanks again, really enjoyed your writing! I came to you through the CA Native Plant group on fb.

Maureen Hurley said...

Thank you Suzanne for reading my piece and commenting on it. It's still very wet behind the ears, and I suspect I'll be revising it for a while. That part you were confused by, I was being cheeky. Will need to clarify that. Thanks for the feedback.

Are you saying that these parts don't contain urushiol? The pollen and honey don't contain urushiol, and apparently the fallen leaves in fall. But I'm not going to test that one out.

Yeah, i too cringe when I read that Europeans "discovered" something. Hence the CA Native paragraph that follows. One reason why I went for a bit of comic relief.