Poison oak
Toxicodendron diversilobum · Anacardiaceae
The gardener's calendar
In autumn, ease off feeding and take the chance to clean up around poison oak and prepare for winter.
ID card
- Family
- Anacardiaceae
- Plant type
- Shrub
- Foliage
- Deciduous
- Flowering
- Spring (April-May)
- Adult size
- 1 to 3 m in height
- Growth
- Moderate to fast
- Hardiness
- Very good (-15 °C)
- Origin
- Western North America
Care
Exposure
Place Western poison oak in full sun or partial shade for optimal growth. It tolerates sunny and arid exposures very well. A location with bright light promotes beautiful autumn coloration.
Soil
This shrub adapts to almost all soil types, from sandy to chalky. It prefers well-drained soil and tolerates relative aridity once established. Organic matter amendments are generally not necessary.
Watering
Water regularly during the first year after planting to encourage root establishment. Once well-established, Western poison oak is remarkably drought-resistant and requires little additional watering.
Pruning and Restructuring
Prune after fruiting or in late winter to maintain a compact shape. Remove dead or poorly oriented branches. Regular moderate pruning promotes dense branching.
Fertilizing
This hardy shrub requires no special fertilizer under natural conditions. A very modest application of balanced fertilizer in spring is sufficient if it shows weak growth.
Health and Caution
Western poison oak is very resistant to diseases and pests. Caution: all parts contain a toxic resin that causes contact dermatitis in sensitive individuals. Wear gloves and protective clothing when handling or pruning.
Did you know?
Western poison oak is notorious in North America for the powerful allergic reaction it triggers: its resin contains urushiol, a highly irritating compound that inspired its scientific name "Toxicodendron." Contrary to popular belief, it is not dangerous simply by looking at it—only direct contact with the plant or its secretions causes problems.
Where to buy it
Best planted in autumn so the roots settle in before summer, or in early spring once the frost has passed. Pick a plant with healthy foliage and roots that are not exposed. Best time: March, October, November.
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Tips generated and checked by Viridia — adapt them to your local climate.