Pacific Poison Oak With Broad Leaves.
In California you will see huge differences in the size, shape, and color of poison oak leaves. It depends on how much moisture, how much light, the type of soil, plus natural variations.
Fall Pacific Poison Oak Leaves.
These leaves have much more pointed leaves, much like eastern poison ivy.
Oak-like Pacific poison oak leaves.
This plant has the typical leaf shape that reminds people of oak leaves. But notice how it doesn’t look like the two examples above.
The Rare But Real 5-leaf.
California poison oak has 5-leaflet leaves often enough that you can spot them (whereas eastern poison ivy has them so rarely that few people have every seen them.)
A Long Center Stem
Compared to the examples above the very long center leaf stem is odd, but poison oak has endlessly different looks.
Poison Oak with a Thorny Neighbor
On the left is a shiny poison oak plant, but on the right is a thorny vine: poison oak NEVER has thorns!
Poison Oak Stalk
When the plant grows as a shrub it sends up very straight stalks. This is a good place to see the way the leafs come off the stem alternating left then right.
Poison Oak Berries
Notice how the berries have deep grooves from top to bottom, like tiny pumpkins.
Poison Oak Berries
Here are bunches of berries in the fall, hanging down. They are good food for birds; clearly NOT for people.
Poison Oak Begins to Climb
Until the vine gets its first wrap around the tree it doesn’t have a strong grip.
Poison Oak Climbing a Tree
Pacific poison oak climbs trees, usually by wrapping around them. (Eastern poison ivy attaches with hairy roots, which seems a much more effective way to climb.)
Poison Oak Swarming a Tree
This shows that poison oak will grow wildly up a tree once it gets started. It doesn’t kill the tree, but does compete for water and nutrients.
Poison Oak Climbing a Tree
The vine is working its way up the tree and will climb as high as it can.
Poison Oak Climbing an Evergreen
This this tree is becoming host to a pretty big poison oak vine.
Poison Oak As A Large Shrub
This poison oak shrub is about 15 feet tall, a common sight throughout much of California.
Poison Oak Fence Shrub
Poison oak will grow along a fence at the edge of very dry fields, as we see here.
Poison Oak At The Golden Gate
The entire hillside facing the Golden Gate Bridge on the northern side was covered with huge stands of poison oak.
Poison Oak Curly And Waxy Near Ocean
Poison oak that grows near salt water will take on a curly and waxy look, just like poison ivy does along the Atlantic Ocean.
Poison Oak Along The Road
Driving up to Yosemite there was poison oak growing up to a certain altitude beyond with it doesn’t grow (same with poison ivy in the east.)
Deep Poison Oak Hedge
Poison oak forms a 50-yard dense hedge between a trial and the drier hillside beyond.
Jogger Passing By Poison Oak
This jogger is passing long trailside growths of poison oak. He has to be careful not to brush against the shrubs or he will pay the price.
Poison Oak Hiding in the Shade
In hot and dry areas California poison oak will sometimes grow in the shadow of other plants that are less sensitive to sun. The poison oak is the darker plant in the bottom third.
Poison Oak Overhead
This trail had a growth of poison oak ABOVE the heads of walkers. Most people would not expect to see poison oak above them. (the plant nearer is a tree; the shrub hanging over in the center of the photos is the poison oak.)
Poison Oak Welcoming Hedge
At the entrance to this park right behinds all the welcome signs was a huge hedge of poison oak.
Poison Oak Square Dance Club
Poison oak is a big part of California lore; this square dance club named themselves after it.
This diagram shows some things to look for: Pacific poison oak rarely has more than 3 leaves in a group. And it never has thorns or saw-tooth edges.