Toxicodendron diversilobum (Torr. & A. Gray) Greene
Pacific Poison Oak, Western Poison Oak
Anacardiaceae (Sumac Family)
Synonym(s): Rhus diversiloba, Toxicodendron radicans ssp. diversilobum
USDA Symbol: todi
An erect or spreading shrub or a climbing vine with 3-parted leaves and brown or whitish berries. Western Poison Oak is not a true oak, but a close relative of Poison Ivy (Toxicodendron radicans). Poison Ivy also has 3-part compound leaves, but the leaflets are not lobed and have more slender, pointed tips. Poison Ivy replaces Poison Oak east of the Pacific Coast region. Poison Oak is so widespread and common in California that it almost qualifies as the state shrub. Anyone spending time in the lowlands and foothills of the state should learn to recognize the plant and avoid it at all costs. Livestock and deer commonly browse the plant without ill effect.
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Plant CharacteristicsDuration: Perennial
Habit: Shrub , Vine
Leaf Retention: Deciduous
Leaf Arrangement: Alternate
Leaf Complexity: Trifoliate
Leaf Shape: Obovate , Ovate
Leaf Venation: Pinnate
Leaf Margin: Lobed
Size Notes: 3-10 foot shrub or climbing vine.
Leaf: Reddish-green early then green, brilliant red or yellow in fall.
Bloom InformationBloom Color: Yellow , Green
Bloom Time: Mar , Apr , May
Bloom Notes: Flower inconspicuous.
DistributionUSA: CA , NV , OR , WA
Native Distribution: Washington to Baja California, east to Arizona.
Native Habitat: Shady to open woods, streambanks, thickets in damp bottomlands.
BenefitWarning: All parts toxic.
Interesting Foliage: yes
National Wetland Indicator Status
Additional resourcesUSDA: Find Toxicodendron diversilobum in USDA Plants
FNA: Find Toxicodendron diversilobum in the Flora of North America (if available)
Google: Search Google for Toxicodendron diversilobum
MetadataRecord Modified: 2007-01-01
Research By: TWC Staff