Trail Mavens


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Trail Mavens Toolkit: Identifying Poison Oak

If you're reading this, chances are you live in coastal California. And if you live in coastal California, it's extremely likely you've been around poison oak, or maybe been subjected to the itchy, bumpy torture that is exposure to urushiol oils. I have once, and the worst part is, I didn't even get it from touching the actual plant. I got it from touching someone else who touched the plant: all the pain of dermatitis, none of the outdoors fun. Point being, the oils are sneaky and tough to wash off. We'll get into poison oak treatment in a future post, but for now, we'll focus on figuring out how to avoid its treacherous leaves. And what's the first step in avoidance? Identification.

Five Steps to ID Poison Oak:

Leaves of three, let it be. The old maxim is remarkably useful, but plenty of vines and shrubs have a trifoliate leaf structure, so you'll need to check out other qualities as well.

Wavy-looking leaves. The lobes on leaves of poison oak are often very different sizes, leading to a wavy, cartoon-ish appearance. 

Shiny leaves. Poison oak leaves contain urushiol (the oil that causes irritation) giving them a slightly glossy appearance.

Green to reddish leaves. Leaves are often an attractive bright green in spring, changing slowly to a darker red throughout the summer. Note that even when the leaves are green, you'll often find reddish marks on the stem or at the junction of the three leaves.

Wherefore art though? Poison oak loves shade and water, so you're much more likely to find it growing in abundance on a trail near a stream than up on high, dry grasslands. 

Questions or comments about poison oak? Let's hear 'em.