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Toxicodendron Species, Pacific Poison Oak, Western Poison Oak

Toxicodendron diversilobum

Family: Anacardiaceae (an-a-kard-ee-AY-see-ee) (Info)
Genus: Toxicodendron (toks-ee-ko-DEN-dron) (Info)
Species: diversilobum (die-ver-sih-LOW-bum) (Info)
Synonym:Rhus diversiloba
Synonym:Toxicodendron radicans subsp. diversilobum



Water Requirements:

Unknown - Tell us

Sun Exposure:

Unknown - Tell us



Foliage Color:

Unknown - Tell us


36-48 in. (90-120 cm)

4-6 ft. (1.2-1.8 m)

6-8 ft. (1.8-2.4 m)


Unknown - Tell us


USDA Zone 5a: to -28.8 C (-20 F)

USDA Zone 5b: to -26.1 C (-15 F)

USDA Zone 6a: to -23.3 C (-10 F)

USDA Zone 6b: to -20.5 C (-5 F)

USDA Zone 7a: to -17.7 C (0 F)

USDA Zone 7b: to -14.9 C (5 F)

USDA Zone 8a: to -12.2 C (10 F)

USDA Zone 8b: to -9.4 C (15 F)

USDA Zone 9a: to -6.6 C (20 F)

USDA Zone 9b: to -3.8 C (25 F)

Where to Grow:

Unknown - Tell us


All parts of plant are poisonous if ingested

Handling plant may cause skin irritation or allergic reaction

Bloom Color:

Unknown - Tell us

Bloom Characteristics:

Unknown - Tell us

Bloom Size:

Unknown - Tell us

Bloom Time:

Unknown - Tell us

Other details:

May be a noxious weed or invasive

Soil pH requirements:

Unknown - Tell us

Patent Information:


Propagation Methods:

Unknown - Tell us

Seed Collecting:

Unknown - Tell us


This plant has been said to grow in the following regions:

Castro Valley, California

Fortuna, California

Fremont, California

Malibu, California

River Pines, California

San Mateo, California

San Antonio, Texas

Seattle, Washington

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Gardeners' Notes:


On Feb 1, 2011, palmbob from Acton, CA (Zone 8b) wrote:

I am surprised there are not more comments about this plant. From a personal experience perspective, this is a species that would keep me from living in certain geographical areas of California thanks to is prevalence in those areas. It is an innocuous looking plant that is somewhat identifiable when in leaf, but very hard to pick out in its leafless form (a good 1/3 of the year in most areas), yet still as dangerous.

The saps from this plant are not toxic to everyone, but abouit 80% of the people who contact it develop an allergic reaction to it. I am included in that 80% though reportedly me father was in the lucky 20% that are not (I never got to test it on him to see if that was true, though).

Having not grown up in northern California where this pl... read more


On Apr 15, 2005, Happenstance from Northern California, CA wrote:

Actually a very nice looking shrub with glossy green foliage in spring and red hues in the fall. Growing at the bottom of our downhill slope, I've left it alone and stay at a distance!