Trails in Northern California

Trails in Northern California

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November 27, 2012

Poison Oak ~ Information, Treatment, and Photos

This page is dedicated to my family, friends, and readers who may be allergic to poison oak and need help identifying it in all of its various stages and forms. Included after the photographs are pointers to help prevent adverse reactions.


Here in northern California there is poison oak 

flourishing along otherwise great hiking trails. 

You're unlikely to find poison oak over 4,000 feet elevation,

but keep in mind a trail's elevation changes.


Taken on the One Eye Creek Trail near Georgetown, CA.

To get to an amazing 100 foot wide curtain waterfall at the other end of this trail, it's wise to dress for poison oak.  Here the poison oak "ground cover" is surrounded by forest, but has an open area of sun.  All of the low growing green plants in the photo are poison oak!  And the trail winds through it.  For hikes like this one, long pants, boots, maybe long sleeves, hat, and gloves would be appropriate. I take a small tarp to sit on.  

 NOT poison oak!
NOT poison oak!
True oaks grow leaves singly rather than in groups like poison oak.

I took this photo of poison oak along Cardiac Hill Trail in Auburn, CA this March 2013! 
 It is everywhere, tall, bushy, vines, hidden, and looming like grand shade providers! for more photos.

Taken on the trail to Fairy Falls, also known by other names, in the Spenceville Preserve near Camp Far West.  That IS poison oak.

This shows you poison oak in bloom. 
And pay particular attention to the three leaf structure.  The top leaf extends more than the others which grow like arms out to the sides.

Here is what is left of this dormant poison oak plant.

SERIOUSLY! Look how invasive the poison oak can be!  It is under the bark of this tree.

Taken at the Harvego Bear River Preserve by Steve Vilter.  Used with permission.
It often is a low growing shrub as shown above, but it can create vines that hang on to trees, although in California, that is still poison oak, not poison ivy. They may also be red or reddish in spring.  They can use aerial roots to cling to trees, neighboring plants, and mossy rocks to climb for sunnier spaces.  The woody stems contain the oil many are allergic to.  Avoid touching any part of this plant including the roots, leaves either alive or dead, flowers or berries.

On the Olmstead Loop in Cool, CA.

Above is another form these plants can take.  The tall branches in the foreground of the pine tree (8-10 feet tall) are poison oak that is dormant for the winter.  Touching it can cause the dreaded rash.  

A close up of the same tall poison oak above
when it was dormant.  It may have an orange or reddish tinge, maybe burgundy,
from the oils, but smoother texture than other bark or branches nearby.

Notice the difference in the large tree trunk and the "branch" growing up in front of it.  The texture is smooth, unbarklike, and sort of rubbery or polished lookingIt is poison oak.  If you look at the base of this oak tree below, you will see a number of shoots heading up from the ground that have that smoother texture and are a different color. When wood is dark, it is the oils that can wreak havok for the allergic. Avoid contact.

The small darker stem growing up the tree is poison oak sending up shoots to climb the tree.

This is a typical poison oak habitat.  It likes shrubs and trees to climb and imitate; one might believe just to fool the allergic!  It takes various forms even in this small setting, from vine, to climbing tall branches that look like part of a tree, or small bushes.  It can be a foot tall shrub or a 10 foot tall one.  The unique leaves and stem characteristics become clear the more you look for it.
In late spring and summer the foliage is glossy and may be turning colors as shown below.  The leaves are not necessarily smooth but may be fuzzy.
Taken along the river south of the Magnolia Equestrian Staging Area along CA 49.

In the fall and late summer, maybe early fall, poison oak leaflets are quite pretty,

displaying an array of autumn colors and are photogenic too! 

As the seasons change
and the leaves fall, be aware that they still contain the oil
that causes the miserable, oozing, itchy, red rash, so watch what you have contact with.

This plant's leaves have the lobed edges, glossy spring growth
and reddish coloring typical of poison oak. 
 In areas where it is growing like ground cover it doesn't look like a threat,
it just looks lush, healthy and pretty. 


  • Avoid any contact with any part of the plant and avoid touching pets and equipment that has had contact with the plant.  Dead plant parts may still have oils that cause the rash.
  • NEVER BURN poison oak that is dead or alive. (Be careful about firewood you pick up.)
  • Take plastic bags for boots and maybe even a change of clothes for the drive home.  
  • Medical sources say use rubbing alcohol as a rinse, followed by rinsing with cold water is most effective in preventing an outbreak. Avoid rubbing too much. Mainly try to rinse as much as you can. Water dilutes the oil but cannot dissolve it.
  • It is not best to use hand wipes. They spread the oil on your skin and rub it into your pores. Soap can't dissolve the oil either, but you can use it if you rinse well and avoid rubbing it in.
  • If you can, prepare ahead by having a gallon jug of water and rubbing alcohol for cleaning up. I do carry it in my car to clean equipment anyway.
  • If your dog is along, and it touches the oils, your contact with the pet can transfer the oils to your skin and it is best to wash thoroughly within 5 minutes
  • Also, using rubber gloves, remove your clothes and launder immediately. The warm water will remove the oil from your clothes.
  • When you are finished handling your clothing, clean oil from the gloves with rubbing alcohol.
  • If you develop a rash from poison oak contact, it can be within hours or may take weeks from the time of contact.  It is not contagious, even if you develop the oozing blisters.  The fluid is your body's attempt to push the oils out of your system, but it does not spread the rash.  If the rash spreads it is simply part of the process your body uses to remove the oils. 
  • Recovery may be fairly quick (average is around 10 days) or may take as long as 4-6 weeks for severe cases.  Over the counter products may help according to my friends who battle this allergy, but most end up getting medication from their doctor. 
If the rash gets around your eyes or genitals, or if you can't sleep due to discomfort, check in with a doctor. If you have difficulty breathing of course, call 911. 

*  I do not get rashes from poison oak contact.  My information is from reading medical reports, websites, and from friends who hike and are allergic to it.  If in question, talk to your doctor for preventative recommendations and treatment.  My hope is to offer photos and descriptions that help you identify the plant and prevent contact with it.

Happy Trails!
 I have learned about poison oak from many sources, but here are some sites you can visit for information:
Updated 12-2012